Gonna analyze the crits here. Set assumptions will be made for obvious reasons.Posting here after after a long time break because this crazy game I am malding over:
https://replay.pokemonshowdown.com/gen9balancedhackmons-2107390029-79xm8st9wwd8wnf965epn1btkm85ajspw
Opponent got all the para's when they needed then, all the crits when they needed them. There is physically nothing I can do about this RNG. Tagging Kris to fix, this is unbelievable.
Kyogre vs Arceus
252+ SpA Choice Specs Kyogre Steam Eruption vs. 252 HP / 252 SpD Arceus-Ghost in Rain: 345-406 (77.7 - 91.4%) -- 31.3% chance to OHKO after Stealth Rock
Even with absolute max spA, it was only a 31.3% chance. Crit very likely mattered.
Kyogre vs Chansey
252+ SpA Choice Specs Kyogre Steam Eruption vs. 252 HP / 252 SpD Kyogre-Primal in Heavy Rain: 139-164 (19.4 - 22.9%) -- guaranteed OHKO
If their set is what I assume it is, crit did not matter. Of course, it easily could have mattered if their set is different. This one is ambiguous, but they're most likely choiced in one way or another
Giratina: 252 SpA Giratina Astral Barrage vs. 252 HP / 252 SpD Metagross-Mega: 242-288 (66.4 - 79.1%) -- guaranteed OHKO
This crit did not matter.
Paras were all rng. And of course, whether each crit actually mattered, I must say.
Unfortunate doesn't begin to describe your sequence-