Even though I agree that bans on the early days of any meta should be delayed and I absolutely love and adore the chaos-pit status of OU right now (and any budding meta, for that matter), Terapagos-S is way too broken to allow it to stay any further and should be banned ASAP. It deserved to be tested because it's a new mon that is kind of a Box Legendary, kind of a Mythical pokemon, kind of a semi-legendary, so we didn't know where it would fit and OU is the "by default" location for such mons; but with the tera form available to it, it leans too badly into "Box legendary" territory to be allowed for longer than a week. If we can make that time-span 2~3 days, then even better!
There are plenty other mons that may require attention, my personal number 2 problem being Deoxys-S, but none of them are urgent and we can have a few weeks/month with them without major issues. Terapagos-Stellar IS urgent, imo.
Also still think that we should do something about hazards, but after LITERALLY ZERO new defoggers came out in DLC2, yet a whole new bunch of Rockers and Spikers appeared, I do fully agree now that "ban Gholdengo" is just not enough anymore. But something will have to be done eventually.
More importantly, while I don't really care about keeping or not the base form of Terapagos, and do think that base Firepon being "balanced and ok for OU" is VERY debatable (it's just better Waterpon offensively, and Waterpon was already borderline), I do think there's a more important point to start considering here, and that is the potential need for precedent on banning exclusive moves and battle forms.
Mega were introduced in Gen 6 as a battle form added to many pokemons. Multiple of these were broken (all additions to the game since Abilities have broken some things here or there), but the mechanic required an item, so tiering against it could be done without stepping into new precedents by just banning the item (although PS! actually has it as "can't have X specific item on Y specific pokemon" complex ban-like). Then they released Mega-Rayquaza, which was the next step in this direction of battle forms that could Mega with no item, instead needing to have specific, exclusive move and "clicking the funny button". But because that was a Rayquaza thing, it was Ubers' problem, and they're the ones that had to come up with a solution. Could've banned the exclusive move, could've banned Rayquaza entirely, could've banned the Mega-form alone. And they made a choice.
Gen 7 brought Z-Moves, which were divisive themselves, but only caused form-changes on Necrozma (again Ubers' problem) and OU didn't have to care about forms. Exclusive moves and abilities, specially abilities, started to become more common, but not really problematic.
Gen 8 brought Dynamax and Gigantamax. Most gigantamax forms were not as broken as Dynamax itself, and the mechanic was simply banned entirely because of how ridiculously stupid it was. But we could start to see how game design for Pokemons started to drift from the more "normal" designs of old times where differences between mons were in the details, into more "blatantly unique" designs with exclusive moves, exclusive abilities and exclusive forms being given to many pokemons. Again, we didn't have to care about the details here because Dynamax was broken on its own, and most Gigantamax were actually usually less broken.
In terms of exclusive moves, Bolt Beak and Fishious Rend were contentious, but we leaned to just ban the broken abusers due to other 2 mons existing that technically could use them, but were too slow on their own to make any good use of them.
But now, in Gen 9, we're still seeing these same tendencies. We had to spend time with Houndstone and Cyclizar banned because of Last Respects and Shed Tail and "policy giving priority to banning pokemons over moves", only to end up months later having to ban the moves anyway when other mons got it (Basculegion) or the other mons with it became OU for no other reason (Orthworm).
We also have the new mechanic of Tera, which effectively gave every pokemon a "battle form change" of sorts, and added additional exclusive forms to Ogerpon and Terapagos, which this time are OU by default of not being box legendaries and so this time, for the first time, OU has to make a decision. And the decision is to "follow precedent" and banned the whole whenever one of its parts gets broken. Which is fair. But let's not forget that there was discussion of making a Tera-banlist back in the day, and banning specific mons that abused the mechanic too much not only was considered, but was argued to be close, if not in form, at least in spirit to how Megas were treated.
Like, what I'm trying to say with all that is that, even if I don't disagree with any of these individual decisions, when seen as a whole, I can't help but feel like the established precedent is reaching the limits of its utility, and that modern Pokemon's game design will force us to shift these policies sooner rather than later. That we will need to be more open to make bans to moves, abilities and forms over whole pokemons as a way to adapt our policies to the new form of Pokemon as a game, whether or not we agree on this new design policy. And if so, now is as good a time as any to start.
But again, just a feeling; not trying to tell anyone how they should do their job. Maybe I'm just hurting from the ridiculous power creep and poor balancing of this gen as a whole and I'm reading too much into it.