I just noticed, it seems TA can adjust the traits of their own vessel,
as in they can reconfigure the basic capabilities of the vessel itself. I think this is the best way to consolidate
the fact we're told TAs have no limits in a way that doesn't contradict other statements. For example the statement from Katatsuki Kouhon:
The 'amount' spoken of in this quote refers less to an end-cap for the TA but rather the quantity of energy they can draw from the planet at any given point; think of it like drawing from a hose so to speak, the size of their hose dictates the amount. Otherwise we would have to assume the quote is contradicting itself. The size of the hose doesn't change, but the vessel itself can be reconfigured to have any parameter they need; which is also consistent with the fact Arc can make her body more temperature resistant if she needs to.
On a different note unless
the TA royalty the Church was mentioned to have driven back in the past were Altrouge and CM, it's very likely there were more TA royalty in the past;
other Brunestud TA. I hope this leads somewhere down the road, would be cool to see other TA in future Tsuki spinoffs.