I don't think there's anything we as the players can do at this point.
I tried everything the person below us mentioned and more and FF is still the only game - the only program even - that is so unstable on my PC. Since Endwalker that is, the crashes occur so often it's unplayable at this point.
I will pause my sub until this gets fixed or at least acknowledged.
I have friend's with very similar PCs that can play just fine, so it seems to a gamble to be one of the lucky persons that can play the game without errors.
Seems like we weren't the chosen ones