It should be so that Paris Saint Germain will not have too much difficulty returning to dominating the league, because they are the best team with a luxurious squad compared to other teams, so for me there is no reason for them not to dominate the league. In my opinion, Mbappe's departure cannot be a reason for them to lose their dominance in the league.
However, if we talk about the Champions League, then I agree that they will have difficulties as usual. With Mbappe in the squad they are still having difficulties, in fact they once had 3 star players at once and it didn't have any impact on them. Now they have to realize that star players alone are not enough to bring them success in the Champions League, so they have to have a winning mentality too, and that must be owned by the team as a whole, not just by individuals or just a few players.
Having any problem with the french Ligue 1 is something PSG doesn't really get to bother about as they have a way around the Ligue one almost a lil the time and know how well to make sure they are able to still maintain their form and their position, they have the advantage of a very good team depth, one that happens to be the best you can find across the French league. The challenge may not really come from the Ligue 1 but they may still have some difficulties because the honest truth is that the team does not have their very for as they once had before now.
PSG is in a position where they aren't really going to be bad but they aren't going to be even perfect aswell, in the champions league, they will struggle at some point, it will be really interesting and funny aswell if they get to play against Madrid which will inturn means having mbappe playing against them, and the very interesting part will be with mbappe winning a d scoring a goal against PSG, I can't wait to have such an experience, lol, I feel the season is going to be filled with interesting moments especially with PSG and their star player who just left the team.