If Mabbpe doesn't want to play in this team they should get him out of the team and take benefits from this player by selling Mbappe with a high price to other teams because none can force a player to stay in PSG.
Even by paying him more money still keeping Mbappe is PSG a wrong move because other players are going to be happy for paying too much attention to one player and this can make the team unbalanced.
Selling Mbappe at too high a price will also not make other teams more interested in bidding for him this summer. But if the price is in a very reasonable category, I think there will definitely be many other teams interested in offering Mbappe in the current transfer market. Moreover, he (Mbappe) is a very good forward line player to break his opponent's defense and even if Mbappe wants to move to another team instead of having to stay at PSG, he also cannot choose a random team if he still wants his career to get better.