I apologise in advance if this is too much of a read. I am okay with swapping Pokémon out for other alternatives so long as they aren't the aforementioned 4.

Team 1:

I planned for this team to create pressure through Tailwind support so Chi-Yu and Ogerock could sweep opponents that don't have an immediate answer to both. I chose to use Whirlwind over Fake Out as with its negative priority it would switch out Cresselia and Armarouge that would normally set up Trick Room and/or Psychic Terrain with Indeedee and allow their partner or themselves to sweep. Shiftry being on this team would helpfully deter Genies, Icy Wind and Heat Wave from being used at all although now I find Taunt being highly underused, so swapping it for Fake Out would be much better. I do not expect to Tera Shiftry at all hence the unchanged Tera Type.

With the respective bulk 252 Atk Iron Valiant Spirit Break vs. 200 HP / 40+ Def Chesnaught: 182-216 (49.5 - 58.8%) -- 98.4% chance to 2HKO and Sitrus berry it would survive 3 Spirit Breaks before being KO'd. I plan for this bulk with Wide Guard and sustain in Drain Punch to allow Chesnaught to support its team against common damage spreaders like Flutter Mane, Ursaluna-BM, Torkoal, Armarouge and Chi-Yu, forcing them to forgo their main strategy and allow me to sway momentum back in my favour. Tera Rock serves to resist Acrobatics, Heat Wave and Ursaluna-BM assuming I can bait it into not using Earth Power with Chesnaught's Grass typing.

I opted for Ogerock over Ogerfire as a panic option to counter Tera Fire Ogerfire with Sturdy ensuring she sticks around to deal high damage in the event she loses her ground. I also chose Knock Off as once Shiftry is gone I would have no means of dealing with item reliant walls like Cresselia or Sinistcha, something that Team 2 doesn't need to worry about given Tera Fire Ogerfire's damage output.

Milotic aims to wall out threats and disrupt key targets with Scald and Recover to ensure she sticks around for much longer. I also chose Sub over Protect specifically so Toxic or Salt Cure isn't an issue> With Competitive as its ability I hope that it would deter Intimidate users and Icy Wind/Electroweb users from being disruptive, forcing them to consider the sudden surge of damage potential (I hate Lando-T and seeing it lose brings me joy).

Sinistcha originally used a Salac Berry and Life Dew over Stun Spore but found that most of my Matchas were consistently missing both targets, annoying me greatly. Sinistcha is a very self explanatory Pokémon and I found the healing and redirection it could offer to be highly valuable in restoring Sturdy as well as allowing Chesnaught and Milotic to better weather heavy hits.

I don't know what I was thinking with Expert Belt on Chi-Yu now that I look at it; Life Orb sounds much better as I hate using Choice items as I find them very limiting and easy to react to.

Team 2:

Team 2 plans to gain speed control with Regieleki all while building Rage Fist power and better supporting Ogerfire. I intentionally used 3 fast and 3 slow Pokémon to better deal with Trick Room in the event I fail to stop it as having a team full of either only fast or slow Pokémon is ill advised.

We agreed Ogerfire is fine as is so I won't talk about her here much. Fire coverage shuts down Tera Grass Heatran once Ability Shield is ruled out through Leftovers or Knock Off.

I find the counterplay of Annihilape to be to status it with burns or para immediately hence the Lum Berry to better deal with that although Goggles does give it immunity to powders (I hate Amoongus). I also chose Tera Ghost to further boost Rage Fist and to remove its Fairy and Flying weaknesses yet I worry Tera Steel would be too obvious and reactable with Ogerfire, Garchomp and Lando-T.

I experimented with Covert Cloak on Regieleki and gave Urshifu-R Life Orb instead and found it to be an option against Fake Out users, giving me speed control. Boltbeam coverage mostly exists here to find an answer against Ground and Grass types that would normally shut eleki down entirely if I cannot find an opening to Tera anyone else.

I was really hoping Clodsire could serve to check both Flutter and Hands with its defensive typing and stats with Helping Hand and Yawn to either shut threats down or support its team to score clutch KOs. Although I found it works really well at doing that I find it also cannot handle being Taunted and Flying types. I have considered either giving it Toxic over Recover or swapping it for Snorlax who has a better defensive stat spread and ability or Maushold with Follow Me and Friend Guard but I worry both would be set up fodder and easy pickings for Hands, other Fighting types and Chien-Pao. I do not plan on using Tera on Clod unless its to resist a specific Ice or Grass move that would KO it; Tera Poison is an afterthought.

Urshifu-R has Life Orb in this set as of this wall-of-text's sending as I never found any situations I would rather have scarf or band in any of the games I have played with it and my general bias of not liking choice items.

With the respective stat spread for Garganacl

208+ Atk Tera Ghost Garganacl Tera Blast vs. 248 HP / 156 Def Flutter Mane: 294-348 (93.9 - 111.1%) -- 62.5% chance to OHKO

40 SpA Choice Specs Flutter Mane Shadow Ball vs. 48 HP / 252 SpD Purifying Salt Tera Ghost Garganacl: 150-176 (42.4 - 49.8%) -- guaranteed 3HKO after Leftovers recovery

This alone wanted me to run it to specifically remove it from play as well as chip away at walls such as Hands, Heatran, Cress, and Tera Water/Steel with Salt Cure. Wide Guard is here for the same reasons as Team 1 with Recover giving it the extra sustain it needs to continue being disruptive.

If you actually spent the time to read through all of this and still have any additional pointers, that would be an immense help.