PSG had three superstar players on the team and they tried their best to have a better performance in the Champions League but still, they couldn't do that and even the players they had like Messi left the team. I think now after Mbappe leaves, they will have bigger problems but as Enrique said, they will try to fill the place of Mbappe in the team by using all the players they have by having better teamwork.
PSG should be able to focus on finding someone who can replace Mbappe on PSG's front line, because without Mbappe it seems PSG will be a little less strong than usual, even though there are several star players there, so far their strength on the front line depends on Mbappe, Mbappe's departure will of course It will be a tough job for PSG to find a replacement this summer, at least he can play and be as productive as Mbappe, who is productive in scoring goals against opponents.
Enrique must be able to find new players and recruit them so that he can fill the current main squad, of course there must be a major overhaul to make PSG even better next season, it's not easy to maintain PSG's dominance in Ligue 1 either, of course that's what they usually do. Apart from the UCL, competition in the UCL is clearly very tight, so PSG must be able to get lots of new and productive players to make this team stronger even without Mbapee next season. PSG must be able to stand without Mbappe.