Can PSG do that with their current condition, yes for Ligue 1 it still shows that PSG is the strongest and has dominated for several years but UCL is competition that is followed by several strong team from various League, PSG with various great players alone cannot win UCL and moreover now with conditions like this it will clearly be more difficult for PSG to achieve that success.
Tomorrow they will face Liverpool in the first leg and for the last 16 if PSG can knock Liverpool out it is already the best achievement because so far Liverpool is the strongest and most consistent team, but if in this first leg PSG cannot win then for the second leg PSG will definitely be lost and they will be eliminated.
I would say, if they failed to win UCL with Mbappe for that many years, and they somehow magically end up winning this year, that would be a huge hit on Mbappes career without a doubt. But to be realistic, PSG has very small chance to win the title this year, they lack a superstar level player and most of the time teams that win the UCL have some sort of superstar that helps them get there and win that game.
I am not expecting PSG to get to next level, even quarter finals is very tough, Liverpool is a great team and PSG will probably lose out there. If I am betting on that game, then I am betting on Liverpool to win, because while PSG is on form and have a great momentum, they are not good enough to beat Liverpool this season.