Being the oldest player in Madrid is a big challenge for Modric, especially since he is rumored to be retiring after his contract ends next year. So far I really like Modric's performance, he is really able to bring the game to life and Ancelotti really loves him. As a midfielder, Ancelotti really trusts him to help Mbappe, he is a very important player and I see he is quite familiar with Bellingham.
Modric has quality in the midfield as a rhythm maker so his presence can help Real Madrid dominate the midfield.
However due to his age, Modric is no longer playing full time because Ancelotti is preparing a replacement for him.
Modric's presence can also help strikers because the beautiful passes he gives are very accurate so it will be much easier for strikers to score goals.
Mbappe's presence will make the Real Madrid squad stronger so that next season it will be much easier for Real Madrid to compete in any competition. Although it is not certain that his presence will be able to defend the Champions League title.