I'm not sure he has disrupted the Juve dressing room tbf mate and other than that he's only ever been at PSG where he was ostracised because he didn't sign the new deal. Carlo introduced him at PSG IIRC when he was only a young lad.
I was similar in not particularly rating him greatly but he does seem to have improved at Juve, and has become more of that ball carrying midfielder that he should be. He's got his place back in the France squad too.
The issue of him maybe being a big fish is a problem I'd agree, though we obviously wouldn't know that for definite - that'd be on the club to do their background checks etc.
One random thing I always remember is, perhaps back in 2016 or something, it was something really random but he was on a video for a new FIFA game I believe. Can't remember why I saw it, but it was basically asking the PSG squad what they thought their ratings would be/should be. Know it's a daft thing, but as you'd expect most players went for ratings that were better or whatever, and Rabiot was really quite modest and said something like: "I didn't have the best of seasons and I should be a 78" - EA had given him like an 83 or something
It's obviously a very minuscule example, but believe the actual issue has always been with his mother rather than the player himself, who supposedly is quite a humble lad. Just very headstrong in that he thought he would be one type of midfielder whereas PSG saw it differently (can't remember if they saw him as a six and he saw himself being more attacking or if it was the other way round).