moving to tera thread so the normal one doesn't get derailed again
i agree that tera needs restrictions. a majority of the playerbase agrees, and if a suspect is ever held i can almost guarantee that we'll end up with tera preview this time. but the fact that lower tiers are far more stable relative to ou proves that tera is not the problem behind why ou is the way that it is. if tera was truly a meta-breaking nightmare mechanic, it would be fucking up every tier, not just one specifically.
You been saying this fir a long time now, even though quite a few bans in all of the main stream tiers have Terastillization as a major aspect of why said Pokémon had to be banned from their metagame.
Calyrex-Shadow is self explanatory.
Iron Hands and Hisuian Lilligant were already borderline offensive Pokémon, and thus could be argued that they may be worth banning regardless, but their ability to run different viable Tera Blast options to break the few genuinely solid forms of counterplay that existed in the tier + the nature of giving essentially free turns via Tera to potent set up sweepers such as them is a major reason why they ultimately had to go.
Gyarados was noted by the RU playerbase to be more Tera reliant than the average set up sweeper in the tier, never the less when it did Tera it was so rewarding that it simply could not be ignored. From Tera Flying to Tera Fairy to other more Niche options, Gyarados could bypass walls and the like that may more comfortably check its coverage options. Iron Leaves is another example, taking its painfully exploitative typing that helped keep itbin check in regards to priority and counterplay and flips it on its head, limiting what revenge kills it and what it could break. Mew's Nasty Plot Tera Fairy Draining Kiss set and it's suicide lead set (bolstered by the above Tera sweepers) were what led to it being banned from the meta, since the former was near impossible to take down and wall after a Nasty Plot or Two and the latter for more obvious reasons. Polteageist ofc was Toxic for its obnoxious Tera Fighting sets giving it super coverage to break the one type designed to counter it.
I'll bunch all of the Oricorios together since all of them have been banned from a lower tier at some point. These are the textbook definition of Tera granting STAB coverage to Pokémon not designed to have them. All these birds use Tera to flip the effectiveness of their counterplay while gaining the coverage necessary to eliminate the few natural checks to their STAB coverage. Its yhat limited counterplay that pushed them over the edge. Jolteon is another example, give it the means to break Grounds and it's no longer the mediocre mono STAB noobbait Electric pivot it's famously known as, it's a Calm Mind super sweeper with unwallable BoltBeam STAB. Dudunsparce is in a similar boat, using Tera to flip its defensive mat hips and turning a strong but ma.agable sweeper into something that is extremely difficult to find consistent answers to. Players have noted Tera Poison and Tera Fairy as strong tools in its kit to help it bypass normal means of lower tier counterplay.
Lilligant is similar to this, a Pokémon normally balanced by its abysmal coverage options and mediocre STAB gets banned when it gets the ability to remedy these issues. Apparently Lilligant was a cluster fuck of Tera options picking and choosing what counted as a check the more the metagame developed.
This isn't observations I gathered from long term Exposure to these tiers, all of this I picked up from skimming te appropriate threads in a couple minutes. So who knows what's currently fucking up lower tiers rn thanks to their access. Apparently Moltres-Galar is up next for a Tera based ban, and I know previous iterations of SVUU Hydreigon was banned cuz Tera Steel was apparently unstoppable. I've seen you use this argument about lower tiers multiple times to defend Tera, and it's gotten annoying at this point because it's not only irrelevant with how OU handles tiering, it's just not true, and any passing familiarity with how any of these metagames work would have told you that.