So I do not see any other options for the PSG club other than selling him. Two years ago, it was about money for Mbappé. But now I believe it is not about money anymore because he has a lot of it.
Yes situation for PSG is much more worse regarding Mbappe. They can act cool here by giving Mbappe an option to either extend or will be sold but in actual they are the one on the bitter end here. About 2 years ago, was it money? Not sure but seems like it. There could lot going on behind the scenes to convince Mbappe. But the fact that Mbappe took a U-turn after having word with Real Madrid president it seems like a huge raise and some conditions was the basis on which the extension somehow happened.