the situation will be difficult for PSG if Mbappe leaves them. especially if PSG is not ready to replace him in the team. they will negotiate for Mbappe to stay with PSG. but Mbappe wants development and challenges. and the Premier League is a good place for him to develop alongside tougher competition. we have to realize that the French League is not as tight as the English League. maybe Mbappe realized that.
Mbappe really wants to leave PSG on the grounds of growth and further development in his career as this has always been the bases and reason for wanting to leave PSG because the French league in it's entirety isn't helping with development and it's aswell looking more like a mediocre league as the day goes by.
Premier league isn't a place for development either, if mabppe moves to England he will only be in competition and not develop, england isn't a place for development but advancements due to the nature of the league, it's competitiveness and the level of attention it attracts aswell ares such that only players who are looking forward to advance on bigger platforms gets the best out of premier league but for developing players they may not Excel that much as they will in other leagues ,I think mbappe will do even better if he goes to Spain rather than england.