I think he might stay in PSG because the money is just too good to be avoided. But a player like him will surely be interested to play for a team like Real Madrid. and I really hope that he will play for Real Madrid because he is not going to be achieving too many things with PSG in the future in my opinion.
Anyway, whatever happens, we will be able to hear the official announcement in a week.
Money is not the main issue he is looking for, otherwise he would have announced that he had sign another extension contract with PSG since few months ago or Im pretty sure that PSG would be posting this all over the social media if they had managed to convince Mbappe to stay. The new club that he is going to sign with is going to pay less than what PSG paid him for but its still a huge weekly wage for sure
At this rate, its either Real Madrid or City but since City just signed Haaland then that means Real Madrid is the only team left