The financial situation of PSG is what makes them different from other clubs of Ligue 1. The difference is honestly too much, even more than Bundesliga. Bayern has dominated the Bundesliga for a long period of time, but the competition gap has not been this much. I don't think Mbappe's leave would stop them from winning the league, but it would definitely be tougher to win it.
However, PSG has already said that they would sign 3 new promising players. If Enrique does his thing and creates team cohesion with his new team, I don't think there would be a problem for winning the league. But winning the league has become so common for them that it does not feel like an achievement anymore. They have struggled to win the Champions League even with their prime team so I think the focus should always be on that for a team like PSG.
Yes, in the future PSG will bring in new players after Mbappe and perhaps the aim of bringing in these new players is not only to replace Mbappe's position but to try to arrange stronger players to create a more consistent performance and build a high mentality to face matches in the Champions League.
As long as PSG can keep Enrique in the next few seasons, PSG will definitely have a chance of at least reaching the final round in the Champions League.
Mbappe departure will really leave a difficult situation for PSG, so it is only natural that now they have started looking for and observing all the players to be able to find replacement for Mbappe who can really help and enable PSG to have strong performance without Mbappe.
Do you remember that Enrique mentioned several times that all PSG players must be able to learn and start getting used to playing without Mbappe, Enrique said that they all must be able to play well without Mbappe.
But in reality PSG is not strong team without Mbappe and Enrique is too confident if he wants all PSG players to play well without Mbappe, PSG have played several times without Mbappe and they looked bad.
Enrique really has to bring in players who are equal and have very good playing qualities if they want to be able to play better and stay close to winning the title in every competition.
After all, Enrique is great coach and he should know what to do and what he must have so that PSG can continue to have high quality performance.