Electric Surge Balance / BO (idk what to call it in this meta)
Random Elo (it's not great, but whatever)
bad GXE :(
Basically, the core of Pincurchin (set terrain --> Eject Button + Terrain Extender) gives 7 turns of Terrain for Tera Electric Rising Voltage Raging Bolt, which with the modifiers (Terrain + Zap Plate + Magnet + Tera Electric) hits over 200 BP. You do some insane stuff like 2HKOing opposing Raging Bolt after Calm Mind and at neutral 2HKOing Assault Vest Iron Hands.
Iron Treads is a nice catch-all check to special attackers, mainly opposing Raging Bolt. Leftovers + AV is good. Also the team's removal.
Enamorus with max boost tera fairy Moonblast is a drug. Could be Boots > Wise Glasses.
Alomomola is still Alomomola (and is stupid) esp being able to stack items giving it nice defensive utility.
Slither Wing is MANDATORY priority. Slither Wing over Lokix to slightly better check offensive Great Tusk (don't be fooled, if it's offensive stacking you still take 60+% from Tera Ground Headlong Rush or something stupid).
Replay (I don't save them unfortunately)
http://replay.pokemonshowdown.com/gen9biomechmons-2513368629
Thoughts on the meta:
TERA: It's an unnecessary power boost on top of the item stacking (Life Orb + Type Items). Meta would probs be better without it.
Rain:

water spam is absolutely ridiculous, the insane number of abusers (Inteleon, Ogerpon-W, Basculegion) wins against basically every team without a Raging Bolt / Rillaboom / Lokix.
- Inteleon (Scarf / Razor Claw / Scope Lens / Mystic Water / Splash Plate or Life Orb / Snipe Shot) + Rain OHKOs or 2HKOs the entire metagame bar immunities. For reference:
252 SpA Mystic Water Sniper Tera Water Inteleon Snipe Shot vs. 252 HP / 252+ SpD Eviolite Chansey in Rain on a critical hit: 321-381 (45.5 - 54.1%) -- 46.9% chance to 2HKO
(I don't know how to add a second boosting item Splash Plate, but given a second 1.2x boost this cleanly 2HKOs)
IDK what I would do to tier this, but removing Tera would help mitigate the damage... kinda...?
SunRoom:

I mean, same thing as Rain except you Trick Room / Room Service / Eject Pack and try to win. Specs Torkoal with a max boosts hurts as well. Less consistent than Rain, though, because a lot is sacrificed to get up 1 clean TR setup.
Overall fun meta though, enjoy :)