It really was TLJ that fucked the entire thing.
TFA was maybe playing it overly safe and cashing in on nostalgia / retreading 'greatest hits', but it was a solid foundation to build... well, fucking something from, and as much as I hate JJ Abrams mystery boxes style, there was enough stuff thrown out that any of those threads could have been picked up and expanded on, or ignored as red herrings by anyone who wasn't actively trying to be an asshole in part 2 of a trilogy and paint the whole thing into a corner, which it honestly seems like what Rian Johnson deliberately did.
ROS is a fucking mess, but was always going to be a mess as it had to be a trilogy in one fucking film, as Part 2 shut down Part 1 of the trilogy, and left very little narrative space left to go, so you had to recover from all of that.
Absolutely fucking crazy tbh.