PSG team is only able to perform best in League One. But the PSG team is not able to do anything in other leagues. PSG have enough players in their squad who can do great things. But due to some mistakes of the coach of the team, the team is currently failing to do well in other leagues.
I don't really understand whether every club's failure in prestigious competitions is the coach's fault. Then what about a club like Paris Saint Germain who have never win the Champions League, for example, even after change coach?
Excess star players is also not always good for a team, it will actually create new problems with the team
About the number of star players in the PSG team, I don't think it's a problem, because at least Real Madrid has proven it for a long time. So, if PSG is still not good at competitions other than Ligue 1 then at least, PSG still doesn't have a good coach, board and/or management to be able to unite the star squad it has.
Therefore, with so many star players in the PSG squad basically it's not a problem, because the problem is that PSG still doesn't have the right method to be able to form a better team for all the competitions it plays.