To be fair after season 6 they were forced to write GoT on their own and only had the broad story points from GRRM
Yes, of course I'm aware of all that. I'm not judging them for something that happened in the past, and I haven't actually seen GoT so I have no opinion on it anyway. I'm just saying that, given the audience reaction when they had to diverge from the books (which I merely note objectively as a thing that happened), it's reasonable to expect that they wouldn't do the same this time without good reason. And since, as you say, the whole trilogy is already completed, there's no reason they'd have to diverge as they did in that case.
Or rather, if they did diverge, it would be for a different reason, to adapt the books' far-ranging ideas into something more filmable or relatable. But the precedent of season 1 shows that they'd probably still base it on the core storylines and concepts of the book, just rearranging things to be more linear and character-driven.