Mbappe was given too many privileges in PSG, and that is what has affected his attitude. At any time he wishes to leave, they are always quick to seek for a way to make him stay. He knows how important he is to PSG as they have shown, that is why sometimes his attitude even towards the manager of the club may be disrespectful. PSG should him go, the manager they have is not strong enough to control him. If it was Erik Ten Hag or Pep Guardiola or even Mourinho, coaches who have a successful career and do not want any payer to ruin it, they will be able to control him.
I also think the same thing as you because so far he has always been privileged at PSG so that it makes him difficult to control, so this will obviously be detrimental to PSG as well if he goes free agency and ends his contract with PSG, so the steps PSG must take are currently pressing Mbappe to extend the contract or sell him immediately.
I don't know how Mbappe thought all this time he was growing up at PSG, which made him very difficult to control for PSG itself, especially if he had the coach mentioned above it might be very easy to control him, if Mbappe joins Madrid next season maybe he can be controlled by the Madrid coach at least, he's not as special as PSG who have always been special about him so far.