And what will we see from PSG in the coming year? Mbappe has said that his next step would be to play for Real Madrid? I think Mbappe may never do that again at all. Only the only big problem Mbappe has is that he will not face any opposition in the cometition in France. So he can really only enjoy his level when he plays in the CL. Then you really should go to Italy or England. Spain is qualitatively a size below it. But I don't see an Mbappe in England happening anytime soon. Haaland and Mbappe together in the striker at Manchester City would not be bad. 
We never know, they haven't even decided who will be the new coach. however, rumors of Galtier's dismissal have been circulating and have been confirmed by Fabrizio Romano. I'm pretty sure if Mbappe will stay with PSG, at least we'll still see him wearing a PSG shirt next season. now, Nagelsmann is the strongest candidate as their new coach. it is even reported that there has been no contract agreement with PSG, but his agent is already in Paris to have a serious meeting with the club.
If in the end there is a deal, I'm pretty sure if he can bring PSG much better than Galtier. but there is one problem, can Nagelsmann have full control in the dressing room. if so, I am optimistic that PSG will be able to bounce back. regarding players, they can bring in anyone after all PSG has abundant finances. The problem is, so far no coach has been able to bring PSG to lift the Champions League trophy. maybe with Nagelsmann and a series of new players brought in, PSG's lucky season will come. but by the way, this is just a personal opinion, even the league competition just ended. so, we'll see how it turns out later.