It will be hard for Paris Saint-German to win the Uefa Champions League trophy. Paris Saint-German has built its team around Mbappe, and if Mbappe is not in form Paris Saint-German will not perform well.
Actually for now i doubt if PSG will be able to win the champions League because for now there are more other clubs which are more better than them in times of performance and besides with the current news or rather rumors I heard that Mbappe will be leaving PSG soon although I don't know how true it is but however if is true is actually going to affect the club a lot in times of performance and besides the clubs that has an upper chance of wining the champions League are Bayern Munich and Real Madrid so for now I don't think PSG will able to beat those clubs.