I believe Mbappe will have put into consideration so many things before he still want to remain in PSG. The pay is fat and he is still the most expensive player in the world. He believes that he still owes PSG and needs to complete his contract with them. He is a superstar that has a good potential and I know that PSG wouldn't let him go easily.
Mbappe should start thinking on how to win UCL and also win other trophies so that he will have the dreams of playing in Real Madrid after the end of his contract with PSG. Other clubs needs his skill and contributions to the team work and he shouldn't just be static in his football career.
Mbappe gives a shit about the contract with PSG and his motivation to publicly say that he wants to stay there for the next season has nothing to do with his belief that he owes PSG to complete the contract with them. He is in it for the money and is now trying to find out how to maximize his income. He also isn't static in his career, but he decided that money was more important to him than building a legendary status, but now he realizes that he will soon be playing for a decade without a Champions League title and he wants to do something about it.