PSG can at least try to sell him slowly. It will also give PSG more benefit caused by the club still needs him right now. You can see the highlights from the previous games about how PSG when mbappe was not playing. It was just proving if mbappe is a key owned by PSG.
The last year PSG had messi or even neymar but this time it's only having mbappe as savior for the club. Do you know how horrible the performance of PSG is? It was not even able winning the game against the worst team in the league.
Mbappe will be leaving from the club. I see no reason for him to stay even longer in the club. He can also get lots of trophy once he will join in the right club.
Saudi has sent him an offer but mbappe rejected it.
It is natural that PSG wants Mbappé to continue contributing to the team. Not only that, they also want to continue to get his signature. If Mbappé leaves, they want to recoup part of their previous investment.
Yes, I have seen some benefits of the club having him. But he also needs a club that will take him to big trophies, something PSG is unlikely to do for him.
Real Madrid is the name on the list he wants to go to the most. Manchester City and Barcelona are also very suitable for him to conquer Europe.