Latias
Attract is really bad and situational. Calm Mind users should generally have bulk EVs and maybe some speed instead of some Special Attack investment. Latias as a whole sucks. The only Psychics in the tier with a notable niche are Calyrex-Shadow and Necrozma-Dusk Mane. Dusk Mane has an important role in checking Zacian-Crowned as well as having other important utility like reliable Stealth Rocks and Knock Off.
Necrozma-Dusk Mane @ Leftovers / Rocky Helmet / Heavy-Duty Boots
Ability: Prism Armor
EVs: 252 HP / 252 Def / 4 SpD
Impish Nature
- Sunsteel Strike
- Stealth Rock
- Knock Off
- Moonlight / Morning Sun
Rayquaza
Why Rest? Why on earth do you have Return? What the hell are those EVs? There's no point in using bulky Dragon Dance when Rayquaza needs all the power and speed it can get. The standard 252 Atk / 4 Def or SpD / 252 Spe EVs is much, much better as a result. Return literally does not cover anything at all super-effectively with no useful secondary effect, and Rayquaza is too frail to be able to use Rest effectively.
Rayquaza-Mega @ Life Orb
Ability: Delta Stream
EVs: 252 Atk / 4 SpD / 252 Spe
Lonely Nature
- Dragon Ascent
- V-create
- Draco Meteor
- Extreme Speed
Rayquaza-Mega @ Life Orb
Ability: Delta Stream
EVs: 252 Atk / 4 SpD / 252 Spe
Adamant Nature
- Dragon Ascent
- Extreme Speed
- Dragon Dance
- Earthquake / V-create
Gardevoir
Once again, bad EVs, unviable Pokemon, too frail to use Rest. If you want to use a Fairy type, use Zacian-Crowned. If you want to use a Psychic type, use Calyrex-Shadow.
Zacian-Crowned @ Rusted Sword
Ability: Intrepid Sword
EVs: 252 Atk / 4 Def / 252 Spe
Adamant Nature
- Behemoth Blade
- Close Combat
- Wild Charge
- Swords Dance / Assurance
Mega Blaziken
Not only is there absolutely no reason to use this over Mega Rayquaza as a mega, but Mega Blaziken is also extremely outclassed as a physical Fire type by Primal Groudon. The EVs are still bad, too frail to use Rest and Will-O-Wisp, and Focus Punch and Flame Charge are pretty bad. You can go several ways with this. If you choose to use Draco Meteor Mega Rayquaza, you can use Yveltal, whose ability to check Calyrex-Shadow and become a terrifying wallbreaker and Dynamax sweeper with a good matchup against Ditto along with its unpredictability make it the best Pokemon in the meta. If you're going to use fully physical Dragon Dance Mega Rayquaza, you can use Arceus-Ground for its great matchup against Primal Groudon and Zygarde, which Zacian-Crowned and Dragon Dance Mega Ray struggle against.
Yveltal @ Life Orb
Ability: Dark Aura
EVs: 4 Atk / 252 SpA / 252 Spe
Mild Nature
- Dark Pulse
- Oblivion Wing
- Heat Wave
- Sucker Punch
*You can also use a full Special set with Roost > Sucker Punch, 4 HP instead of 4 Atk, and a Modest Nature.
Arceus-Ground @ Earth Plate
Ability: Multitype
EVs: 252 HP / 240 Def / 16 Spe
Bold Nature
- Judgement
- Recover
- Refresh
- Ice Beam
Gengar
Gengar is way too frail to use whatever that is. The EVs are strange. Gengar is outclassed by Calyrex-Shadow, which is extremely versatile, powerful, and restricting. It can run a variety of sets like Choice Specs, Buginium Z, and Life Orb Nasty Plot, but my favorite is Quickpass. Calyrex can still do tons of damage with Ghostium Z Astral Barrage, while also being able to use Nasty Plot, and Baton Pass to Yveltal and pretty much win the game.
Calyrex-Shadow @ Ghostium Z
Ability: As One (Spectrier)
EVs: 4 Def / 252 SpA / 252 Spe
Timid Nature
- Astral Barrage
- Nasty Plot
- Baton Pass
- Substitute
Primal Groudon
Wacky EVs. Defensive Primal Groudon is a pretty good Rest user (albeit without Sleep Talk), but offensive Primal Groudon shouldn't use Rest. Eruption Primal Groudon also generally fits on hyper offense. You've already got a great Zacian counter/check in Dusk Mane, who also sets Stealth Rock. Due to this, I think Primal Groudon is replaceable. You can probably use Ho-oh in the last slot, since you don't have a Defogger.
Ho-oh @ Heavy-Duty Boots
Ability: Regenerator
EVs: 248 HP / 208 Def / 52 SpD
Impish Nature
- Sacred Fire
- Toxic
- Defog
- Whirlwind / Roost / Protect
Something else
Since some of the Pokemon I suggested can fit well on hyper offense, I made a Sticky Webs hyper offense team.