PSG's main problem is that there are too many star players in the squad. Those don’t want to be controlled by coaches. I heard rumors a few days ago, that Mbappe took PSG's internal decisions, the role of the coach is very small. If this is true then it is very scary for any team. The coach must be allowed to work independently. Christophe Galtier is probably not very experienced. But given the opportunity to work independently, he may also want to win the Champions League title
I think the problem is not in the many star players in the PSG squad, but their weak defense and lack of creativity in midfield. now PSG have bought Vitinha for the central midfielder he can also play flexibly can play as a defensive axis.
I think the PSG coach has corrected the weakness of their team, and for mbappe I think it's just a rumor and this news has been widely discussed.