Modric is getting too old, so it's understandable that he's leaving, and it won't change anything. In fact, it's a good thing for Real Madrid to regenerate the team, especially in their midfield.
A new era for Real Madrid is slowly being built, and I'm quite optimistic about it. Real Madrid has been developing many young players for the past few seasons, so it won't be difficult for some of the senior players to leave.
Xabi Alonso is also a coach who is quite adept at combining young and senior players. This was evident when he was the manager of Leverkusen last season, so what he will do with Real Madrid is likely to be the same.
Alonso is trying to change something, but I am not ready to evaluate the results of his work yet, he is bringing in young players and it worked with Garcia in attack, but despite all his efforts and transfers, Real's defense still does not have the same strength. It is too risky to bring in young players to defense, so I think that the introduction of young players will be gradual. On Perez's part, bringing in Alonso is still a risky move, in my opinion.