Another month of changes, another shot the community gives me to explain to them why things rose or dropped. I'll try to be thorough but do feel free to ask further questions in the
CAP Discord, forum DMs or even this here thread! Gonna focus mostly about the top dogs and the head-scratchers, but I am gonna at least go over things once. Without further ado, let's go!
Remains the sole S rank; while the metagame has mostly adapted to it, it being able to be splashed onto almost any team save for hard stall keeps it at the tippy top. Choice Scarf Pokemon are very rare nowadays, so Dragapult having unprecedented Speed even for an OU pseudo-legendary leaves revenge killing it hard. I don't expect this to stay true for too long, as teams are starting to be overprepped for it, but for now, he's the king of the jungle.
Rises
A → A+
Lagging ever so slightly behind OU's trends, Weavile has invaded all houses of CAP residents and terrorized its inhabitants. The Swords Dance set has been able to pressure teams HEAVILY, beating down common defensive Pokemon like Corviknight, Mew, Tornadus-T, Zapdos and Landorus-T. Triple Axel is the turning point of the set, even being able to OHKO Corviknight after a bit of chip and/or Stealth Rock. Weavile also gives more offensive teams a consistent way to deal with Dragapult, as it can pressure it with Ice Shard and revenge killing it becomes tough once you realise Rillaboom is much slower and
also susceptible to being Ice Sharded. Nothing this Pokemon does is fair, and the Adamant nature some opt to run is just the cherry on top. Very likely to rise to the S ranks soon.
A+ → S-
Heatran has actually not been the #1 Steel
its usage in CAPPL suggests, however, it's spot in the meta is undeniable. It provides unparalleled role compression, from setting Stealth Rock, denying FuturePort with Taunt, beating down stall through trapping and Toxic and even answering the problematic Steel-types that crop up with it access to Heavy Slam. Not only that, but being able to act as a Dragapult check if the need arises and having a spot in the metagame as an offensive mon make up for the pressure it puts on itself by virtue of just how easy it is to fit on any given team. The posterchild of S-.
A+ → S-
Another byproduct of Dragapult's reign. The only Pokemon that can naturally outspeed Dragapult and threaten it with Knock Off, Zeraora offers great offensive utility with access to pivoting, Knock Off and Toxic. Thanks to its item clause usually being HDB, it can't even be punished by hazards anymore as it can pivot in and out of the field and threaten anything that isn't a Ground-type. Some players have attempted to check it with bulky Jumbao spreads or even Scarfbao, so I don't know how it's gonna continue faring in the future. For now, furries yiff and we're in hell.
A- → A
Similar to Zeraora, Tapu Koko is another scary Electric-type that mandates a Ground-type in every team. Unlike Zeraora, however, this Pokemon can also take opposing pivoters on quite well and doesn't rely on its item too much, making it a decent Knock Off absorber. Thanks to Roost, it can shrug off the chip U-turn from Corviknight and Tornadus-T while always threatening them out. It can also slowly but surely chip Galarking through hazard support and U-turn, while also being able to overwhelm Ground-types like Landorus-T and Colossoil. Definitely my personal favorite Electric-type.
A → A+
Remember how I just said Zeraora is a nuisance? Well, Lando-T says "no" to pretty much anything it wishes to do. Honestly, the only thing this Pokemon cannot do is have reliable recovery. With the rise of Electric-types, Specially Defensive Landorus-T Saves The Day! The utility it provides hasn't changed, it's just changed to a more mixed defenses pivot. Great role compression mon, its definitely worth the rise.
A → A+
The resurgence of the big bird. Offensive sets can still pop off if you don't run into a strong Electric-type, but what's drawn our attention is its pivoting set. Taunt and Toxic are both moves people have been experimenting with, helping to keep slow walls like Hippowdown and Landorus-T honest by shutting down their utility. Taunt in particular is fantastic alongside Spikes balances, stopping prospective defoggers that aren't too scared of Torn-T (see: Landorus-T, Mandibuzz) from removing hazards.
A- → A
Problems with Slowking? Don't like Weavile sending you to the shadow realm? Kyurem is cold to touch? Scizor helps with all of your problems. The mon provides a ton of utility in every playstyle and can even be a win condition with Swords Dance. It does have a few problems like all contact physical mons do, but it's very easy to add to a team and cover a lot of your problems.
B+ → A
With Weavile and Moistshifu rising and set-up sweepers seeing more play, Arghonaut comes in to save the day. Honestly, the only thing this Pokemon is lacking is Flip Turn to become S rank. Hazard support, phazing, great ability, passable Speed tier allowing it remove a few of its fellow bulkies; the Pokemon is a physical version of Heatran. While the many Electric-types do hurt it a lot, they also help it in a sense, as they keep the previously impossible for Arghonaut to deal with flyers in checks. Glad to see this Pokemon finally able to climb through the ranks.
B → B+
Buzzwole is just THAT GUY™. A defensive Pokemon that can invalidate defensive backbones is always welcome and the physical bulk that this Pokemon has is nothing short of amazing. Another answer to Weavile, Zeraora, and the now rising Tapu Bulu, Buzzwole can help mitigate a ton of problems that arise in building now that the name of the game has become "check xy threat" instead of about typing. Toxic and Roost make it a complete nuisance and removing it becomes incredibly tough if you don't have Exactly a Tapu Fini or Lele, Heatran or a Flying-type. That seems like a long list on paper, but with its base 139 Attack and physical coverage that even makes some Ubers shudder, none of them get a free switch-in.
B → B+
Trapping isn't competitive and Corviknight and Skarmory check a lot of your Pokemon so might as well just win in builder, right? Oh, you also wanna beat Equilibra, a Ground-type? Don't worry, Smokozone it up. I'm personally never happy to see Magnezone rise as I find trapping to be very matchup fish-y and uncompetitive, but I understand what the risk reward situation it provides is. If Steel-type usage drops, so will this.
B- → B
Another OU trend, Blacephalon has negative defensive utility besides being... a U-turn resist, I suppose? But the funny clown also has base 151 SpA which allows it to even 2HKO Blissey with a Choice Specs Mind Blown. Good hazard removers are easy to come by in the metagame so keeping it relatively healthy with double Defog cores isn't even that hard, whereas switching into this Pokemon is absolutely asinine. Very little defensive counterplay limited to 50/50s and its absolutely abhorrent bulk, a Blacephalon on preview is nigh impossible to switch into.
B- → B
Another Pokemon that I spoke about last metagame evolution and little has changed about it. I personally want to see someone bring it in HO as its a potent and forgotten hazard lead. The defensive sets are still really tough to crack and with Mew picking up Taunt, it keeps a lot of its checks at bay.
B- → B
Comparisons to Rillaboom are very obviously gonna come, but they don't work the exact same way. While Rillaboom is more of an offensive threat, giving you pivoting and revenge killing with Grassy Glide, Bulu has its own merits. For one, it has Stone Edge to be able to nail the Zapdos and Tornadus-T of the world and for two, it gets both Synthesis and Horn Leech, keeping it even healthier when it attempts to slowly win with Bulk Up sets. It's pretty solid if your team isn't in need of the fakespeed.
From the depths of Unranked Hell
UR → B-
Kommo-o is a Pokemon I personally wasn't sure how it works but it's actually a pretty decent threat and wall alike. With bulletproof, it's actually a Shadow Ball immune Pokemon, making it quite potent at catching Dragapult who don't know about it and Blacephalon alike. Not only that, but it's also a decent Stealth Rock setter, being able to phaze removers out with Dragon Tail, working as a worse Garchomp.
UR → B-
I've been advocating for this Pokemon for a while and it's finally ranked again, huzzah! A super sturdy Ground-type that has reliable recovery, Hippowdown can even take an occasional Future Sight now that it's become more of a mixed wall. While it's a big momentum sink, it also completely eats up the opponent's momentum, so it very slightly balances itself out. Kinder Happy Hippo needs some strong support considering how many breakers can come in for free on it, but it's definitely a good fit for teams that need a bulkier Ground than Landorus-T.
and
UR → C
"Why is Arctozolt ranked again?"
Fringe weather abuser, I made him and I broke him. Have fun.
Alolatales on the other hand is a decent double screens lead that can further enhance HO by setting up screens in 1 turn and then using the rest of your turn to set a Hypnosis or Encore the opponent into a bad move.
UR → C
Another Pokemon straight up from the depths of Hyper Offense hell, Haxorus can invalidate some of the better anti-HO mons in Astrolotl and Arghonaut thanks to its good Attack stat and Mold Breaker. With Scale Shot, you can opt for Swords Dance and then go to town if you get enough hits. Now, is it reliable? No, but it's on the fringe of decency.
UR → C
See Rabia's post above.
UR → C
Matchup fish Pokemon that basically tests you on the builder; do you have a bulky Electric, Ferrothorn or Arghonaut? Perfect, you're perfectly safe. You do not? Get ready to struggle while this Pokemon can even Slack off itself back to a healthy amount. Its actual viability depends on what set its running and how easily you can get a DD set up, as it otherwise does less than nothing.
Drops
S- → A+
Still one of, if not the best special Walls. Future Sight support is still insane, RegenBoots is still really and a bulky water will always be tough to beat. HOWEVER! Dark-types, more pivoting, Electric-types and anti-FS mons in Corviknight are making Slowking have a bad time at the moment. It's still very good to splash on, but at this point, it's no longer copy pasted into every build.
S- → A
The man himself faces a tough time, having to deal with MORE strong revenge killers in Weavile and Moistshifu, Buzzwole and Arghonaut blanket checking it (Life Orb mixed isn't a set Copium) and in general, not getting as many free set up opportunities. It can still invalidate a lot of teams, but it can't simply win on the spot like it used to.
A+ → A
Very difficult to put on a team at the moment, the Steel-types in the tier are also not ones that Kyurem can easily beat; Glowking also has a very OK time versus it, albeit the Choice Specs set is still impossible to switch into. Metagame also got just ever so slightly faster so its revenge killers are creeping right around its Speed tier, if not just above it. Weavile also deals its job of "Ice-type with no switches" a bit better, but don't be fooled: you can still use both to great success!
A → A-
Match-up moth was simply put too high too soon and flew too close to itself. The rise in Heatran also hurts it, as its best move to hit it with is Psychic.
A- → B+
"A Knocked Off Krilowatt is a dead Krilowatt" Son Jho - The art of Choke.
Nothing WANTS to take a hit from Kril, until something does and then it becomes another puny shrimp. Not only that, but an Electric and Flying resist that doesn't take Knock Off? In this day and age? Localized entirely in our metagame? No thanks! Good on paper, underwhelming in the field.
A- → B+
Ooga booga monke hates every metagame development besides Arghonaut's rise. Its pivoting gets punished, it doesn't revenge the best Pokemon as easily and in general kind of... hurts from the metagame's evolution. Not only that, but Bulu is the new cool kid in school and while he's not
as cool as the Rilla, Donkey Kong is looking kind of Lanky atm.
A- → B+
Every time this Pokemon gets brought up, I swear it turns worse. Physical attackers that break it? Check. Everything it used to invalidate gets invalidated by better Pokemon? Check. Hazehawk worse as physical attackers have that bit of oomph needed to break it if it's this set? Check. Not ORAS so no Reflect? C-c-c-combo! Honestly, Tomohawk feels like a "too many cooks in the kitchen" kind of Pokemon, where it's not truly bad but every time the metagame progresses, it just gets worse by association. Still has cool coverage, though!
B+ → B
The spooky sword, while capable of breaking through most walls, simply doesn't cut it at the moment. It's very hard to justify on any team, with its SubTect set being quite easy to abuse by a lot of walls and Dragapult being able to go through its Substitute with Infiltrator. Another Ghost-type that isn't named Dragapult suffering because of it.
B+ → B
While still a cool offensive mon and an anti-defog staple, Bisharp competes for its slot too heavily with Weavile while getting checked by the same, if not more Pokemon. Steel coverage is definitely good with the current array of Fairy-types, but its Speed isn't doing it any favors.
B+ → B
More anti-HO tools like Arghonaut and more Heat Wave on Zapdos and Tornadus-T means that mafiozo birb doesn't just go through unprepared teams quite as often as it used to. Make no mistake, however, as it's still gonna sweep on the ladder because newer players don't know what Volt Absorb is.
B+ → B
Ground-type that doesn't beat the 2 premier Electrics and is too fast to abuse Zapdos Roosting, while also a Dark-type that takes a lot from the best Ghost-type. Good for role compression and Rapid Spinner that kills spinblockers is still a fantastic niche, but it's a bit difficult to fit on teams nowadays.
B+→ B
As good as Hydreigon is at breaking down walls, it still suffers from "I have never killed a Clefable and I never will" let alone other Fairies that potentially are neutral to Flash Cannon. Its still quite scary to see on preview, but it's very rarely that a player would rather have it over Dragapult. As such, it's fallen off even more... not to mention how yummy Weavile finds it.
B+ → B
Toxapex is running special defense investement for Pult? Kerfluffle never stood a chance.
B+ → B
If your Dark-type loses after being Knocked Off to the things it's supposed to check, maybe you need a better Dark-type. Mandibuzz doesn't beat common Stealth Rock setters as they are either Clefable and Heatran and can thus 2HKO it or the Ground-types that Toxic it and watch it slowly die.
B+ → B
Another Pokemon competing with Weavile, Syclant differentiates itself by virtue of having a solid way to break both Toxapex and Heatran in Earthquake and of course being able to pivot. Bug coverage is, unfortunately, not that sought after, even if a STAB U-turn is gonna hurt anyone coming in.
B → B-
With sand answers being better than ever, Excadrill struggles to find a spot in the current landscape. It's not the best Ground-type out there, losing to Zeraora and its utility being covered by other Pokemon much, much better. Its Earthquakes are always fearsome, but the anti-ground Pokemon running around don't mind coming in multiple times. Almost no Rotom usage also hurts 'driller, as it can't abuse its Mold Breaker.
B → B-
Another Pokemon whose better on paper than in battle. Nidoking is ridiculously easy to revenge, as almost all special walls have something to deal with it and the two bulkiest targets, Slowking and Blissey, don't mind coming in multiple times and using it as set up for their utility moves.
B-→ C
Kartana seeing some play, bulky grasses having a decent spot and mixed defenses Toxapex existing make rain a relic of the past; with Tornadus-T on the rise, too, giving it safe Hurricanes is never a good way to fish for match-ups. While the playstyle can still beat a lot of offensive teams, bulkier builds don't really struggle to put it in a chokehold.
B- → C
Another Pokemon that hates Heatran while Heatran is rising! Necturna has transformed into a special attacker in Sword and Shield, and it struggles to deal with the birds and the Trans. HO often drops this nowadays in favor of Moltres-G, a Pokemon that also gives you a much needed Ghost resist.
B- → C
I lied about bulky Grass-types, Tangrowth sucks. Everything it can do, Buzzwole just does better. Its awful Special Defense means that it struggles to even take on Zeraora's Volt Switch, while Tapu Koko's Thunderbolt 3HKOs it with ease. Just overclassed by other physical walls while also hating Weavile. Still can deal with Moistshifu, though.
C → UR
If the meta is trending towards Electric-types, it also means the counterplay for them is better. Thus, a defensive Electric offers too little. Goodbye to the nimbus of Zeus, I'll personally miss it.
C → UR
this but Latios sucks rn a bit too hard, use any other Dragon or Psychic type. Hell, use Latias, it can Healing Wish your threats back to full.
-> A
-> C
to A/A+ 
Why is this still mid-A? Because it checks Cawmodore? l2p please LOL it's very mid at every job it tries to do. I only use it over Landorus-T/Corviknight/Zeraora/Tapu Koko if I really need to compress Flying-type check + hazard removal into one slot.
Equilibra is awful. It's super hard to fit on teams and fits really poorly in this metagame because it fails hard against offense. Skarmory is just overrated and has been for awhile imo; the drop in usage of Rillaboom and Garchomp both hurt it a good bit, and I favor Arghonaut as a standalone Spiker/Pokemon that shuts down setup physical attackers more.
Unviable, get it off the VR. Its niche is no longer as necessary as it was in previous metagames, and as a wallbreaker there's not much reason to use it over the other Dragon-types.
Weirdly slept on, provides a lot between Trick + U-turn and soft checking Tornadus-T and some other dangermons.
Kartana: B- -> B+
Moltres-Galar: UR -> B-/B
Necrozma UR-> C
to B-/B Everyone knows how this fire birb works, clicks sd on something and kill some mons. Blaziken cant kill entire teams bc LO + Blitz recoil but +2 CC does already a ton of damage to every wall on the tier. But that not the main job of Blaziken. Blaziken works as a mid game breaker with Watershifu, working as a great double fighting core who can overwhelm common checks like Fini or Pex. 
to ranked somewhere between c or b- Underrated threat on a metagame with tons of electric weak mons and ground types without recovery nor normal resist, stills breaks tons of teams lacking a glowking or equi and even can sweep with Shift Gear.
-> B+