It doesnt really matter, PSG will not sell, PSG is not a club you can negotiate with.
He either leaves for free next season, or renews.
Even if Mbappe came out and Said he wanted to leave, i can even imagine Nasser let him rot on the bench in the final few months of the contract, out of sheer spite.
As Luftstalag said PSG will never intentionally bench him. Only way he is getting benched is if he does it as he did in his last moments at Monaco. He was seemingly playing very bad on purpose to the point it was better playing a lesser player than him.