I think the only parts I'd really categorize as a disaster kinda need a third movie to explain. I really don't like how Denis changed Paul and Chani's relationship, but maybe it'll get paid off in a satisfying way in part three.

Or it'll just continue being extremely out of character teen angst for contrived plot reasons, idk

"Because it's profitable", is my guess. I thought it was a good adaptation, what did you find so disastrous?

Part 2 was not a disaster. Personally, I think both parts were really good. No idea where you're getting such a negative opinion of part 2.