I believe Ancelotti is quite firm and he prioritizes the team over individuals. Mbappe is known to have a bad attitude when he was at PSG, he was too powerful without thinking about the interests of the team, which made PSG slump in the Champions League.
At Real Madrid, Mbappe really has to get rid of that kind of attitude and Madrid is a team that has a long history of winning the most titles in Europe. Of course, it is hoped that Mbappe's arrival will help Madrid continue to defend its title and I am very sure that Mbappe's presence will have a tremendous impact if he remains professional and respects his teammates.
In addition to being firm Ancelotti must also present a solution so that players who have joined Real Madrid do not always fill the bench. I am also sure Ancelotti can solve this problem and he must have a way to maximize the players he has. When he is at Real Madrid and Mbappe still behaves like he did at PSG, then I am sure he will not get a place because there are many great players at Real Madrid.
Mbappe must have learned from experience and the targets that he has not been able to achieve must also be realized at Real Madrid. Selfishness will not benefit him and I believe he will mature at Real Madrid. Professionalism will definitely be shown by Mbappe because he is now more mature and his hope is to be successful at Real Madrid.
It seems like Ancelotti is quite capable of managing Madrid dressing room in harmony, so Perez doesn't have to step in to make a statement that no player is bigger than the club. Mbappe definitely understands the situation well, he has to suppress his ego if he wants to be treated well by other players.
Meanwhile, Ancelotti has proven to be adept at rotating his players, where each Madrid player will get a role according to their abilities. With the many competitions that Los Blancos will participate in next season, I think all players will get a fair opportunity to show their abilities.
On the other hand, Mbappe certainly needs to adapt to the new squad, and I don't think he will need long. If the process goes according to expectations, it would not be surprising if next season Mbappe will become La Liga top scorer. With the addition of Mbappe, Madrid should be able to defend the Champions League and La Liga trophies next season.