This is because Mbappe does not fit with the Real Madrid team, at PSG Mbappe can be a leader and he can even put his ego forward but at Real Madrid this cannot be done because Real Madrid is a big team that gathers top players so Mbappe must be able to adapt to that.
For now Mbappe is very burdened with the fans' taunts but he still has time to fix that, with the individual quality that Mbappe has I think he still has the possibility to be able to turn the current situation around.
This might be true maybe the pattern his use to is different but when it comes to football I don't think that should be an issue because mbappe have spent some time with them even when it comes to training, the time spent during training should be enough to build a better team work, and maybe his personality is what is affecting him you might have a point there because Madrid players won't tolerate any form of instruction from him, his new to the club and some other reasons and that is why I keep saying that wether with or without mbappe the club will succeed because of the kind of players they have.
If I was mbappe I will adjust and try to understand things because for him to be in Madrid he has a lot of opportunity to build is career better, because mbappe is an excellent player and his an asset to Madrid thay is only if he decides to improve is football, and there were players that had almost the same problem with mbappe but they have decided to become better because there is no way you pass through Real Madrid and you will not perform well even if it will take time. He should better start deciding wether to perform well or not.