It seems Sancho doesn't want to move to AS Roma because I heard that AS Roma and Manchester United have agreed on a transfer fee for Sancho, but Sancho hasn't shown any positive sign of joining AS Roma this summer. In my opinion, Sancho wants to stay at Manchester United and see off his big money contract because I don't understand why a player who wants to leave Manchester United would reject a move to Chelsea because of a reason best known to him.
Sometimes a player who has had problems with a club wants revenge in a different way.
This season, Jadon Sancho is due to extend his contract, and if he doesn't agree to an extension next season, he will leave on a free transfer, after which he can choose any club.
AS Roma should likely stop pursuing this player because I believe Jadon Sancho has other plans, and AS Roma is certainly not his destination.
Manchester United doesn't care about Jadon Sancho, so in my opinion I'd say Jadon Sancho should forget about getting revenge against Manchester United by wanting to leave Manchester United as a free agent and focus on joining another club in the top 5 European leagues so that he can revive his football career. Jadon Sancho's plan is to remain at Manchester United so that he can continue earning his big wage and nothing else.