Mbappe is a great player and I'm sure Carlo Ancelotti is delighted to have him now. His rotation is quite wide right now. Considering that Arda Güler plays great in the wing position, they have a lot of options and a young average age. We can say that Ancelotti has established the squad for the next 5 years.
With the way Real Madrid signs players, you will know that they’ve created a formidable squad that will last them for many years to come. They look for young talents then groom and integrate them into the system that will take them years before scouting for new young players. They will be assured of a long lasting season before they even begin to search for another, so staying without formidable squad is what I don’t think has happened to Real Madrid for ages now. Ancelotti knows how to put this players together better, so I feel he will be a good manager for Mbappe also and will bring out the best in him while playing with his other teammates.