How are you guys/girls/enbies dealing with Fairy types?
Depends on the team honestly! Galarian Slowking is great for certain teams, but it doesn't really fit many faster-paced offense builds. You'd notice that those teams instead often pack a Gholdengo to check Iron Valiant in a pinch, a Ceruledge that can tank a Moonblast and won't get OHKOed by Shadow Ball / mixed Knock Off, even more niche picks like Iron Crown see a decent chunk of play. Red Card Glimmora is an offense tech that works well against Iron Valiant in particular, since without Booster Energy to boost its speed it'll often end up getting blown up by a faster Zamazenta's Heavy Slam or Darkrai's Sludge Bomb, and Booster Speed Treads is a nice fast Steel-type that can also do the trick while being hazard control for a team. Kingambit isn't great against the faster fairies, but it will always beat Hatterene.
For balance and bulky offense teams, Slowking-G is a fantastic pivot that handles Primarina and doesn't even mind switching in on a choice-locked Enamorus' Earth Power, but other mons are pretty prominent and can also function as Fairy checks. Gholdengo is still a balance staple that can even run bulkier sets to better check Val and often uses Air Balloon which walls Enamorus pretty well, and Cinderace is well-renowned for being able to take any hit from and remove a chipped Iron Valiant. Corviknight with Brave Bird is a good check for the fast Fairies as well, and so is Moltres which completely walls Enamorus. Balance without Slowking-G can often struggle against Primarina, but Primarina is slow and lacks reliable recovery so it'll often be worn down by hazards or forced to take damage and check things itself before it becomes a threat.
Pecharunt, Weezing-G, and Skarmory are also pseudo-resists on these teams, but none of them have great SpDef so they aren't always the greatest switchins to the tier's Moonblast-ers. Heatran is a less common option on bulky offense that makes Hatterene's life impossible, but it does lose to mixed Iron Valiant or Earth Power Enamorus (after having its balloon popped). A pretty big thing is that this tier is not too packed-out with Fairy-types, with Primarina or Enamorus not being too omnipresent, while Hatterene being so slow makes it something of an exception since it loses badly to the very-common Gholdengo and Kingambit.
all of the offensive ones have common weaknesses that overlap with the stuff you want on the same team as a fairy
In terms of fitting Fairy-types on your team, I'd definitely recommend that you don't worry too much about type stacking, especially when it's on Pokemon without overlapping roles! Iron Valiant and Great Tusk are a perfectly fine pairing as they have almost no overlap in what they want to do for a team. Both Tusk and special Val will often run no Fighting STAB anyway and, if you have a good answer to shared checks like Hatterene or Moltres, this shouldn't cause any issues. Enamorus is also quite fine being paired with other Flying-types since it's not too afraid of Kyurem and cannot run Flying STAB either, of course you should keep in mind the shared weaknesses this does bring but that doesn't mean they can't be used together at all; a more balanced team with a Scarf Enamorus will often appreciate something like a Corviknight to switch in on Poison / Steel moves and bring Enam back in safely with U-turn.
I'd also not discount teams with type overlap, one of my favourite teams I've ever built from back when Sneasler was legal had
4 Fighting-types, those being Great Tusk, Zamazenta, Sneasler, and Iron Valiant. This was post-DLC at the peak of Zapdos meta and keep in mind that this team also had a Rillaboom, making it incredibly weak on-paper to any Flying type, but the whole idea was that these Pokemon were unique enough to fulfil different roles on the team while having checks that overlap enough to break for one another. My Iron Valiant was Choice Specs with Tera Electric, letting it snipe things like Moltres in a pinch, and my Zamazenta was Tera Steel Heavy Slam with some attack investment to remove opposing Val or Enam and beat Slowking-G. Sneasler was my speed control and main sweeper, while Great Tusk gave me hazard removal as well as an alternative win condition.
The gameplan would often be to throw away my Rillaboom, Sneasler, and/or Bulk Up Tusk to take out Zapdos and make way for Zamazenta, it was absolutely not an easy team to pilot but it was incredibly threatening and one of the most rewarding I've ever had the pleasure of using, all despite having 4 Fighting-types, 2 Ground-types, and zero Flying or Fairy resists. It's actually an adaptation of a very successful team from the previous HOME meta that I ended up
writing an RMT on, though this used Cresselia over Val (check this team out if you want to see a very early use of a very modern Cresselia set!). There's a sample team with
Zamazenta, Val, and Hands as another example of this offensive typestacking, though I don't really feel the same way about this as it's a dual screens Hyper Offense team where defensive play is much less important. The point I'm making here is that
type overlap isn't necessarily a bad thing, so long as you have a clear way to deal with the weaknesses that it brings and you aren't trying to use mons that do the exact same thing, it can even be a good thing when those Pokemon have tools to break walls for one another and work together to achieve their win condition.