What Xabi needs to do is turn star players into team players. Managing star players is very difficult. Because they want individual success, they want to attack every position themselves. However, having a unified team is beneficial to the team. That's why Real Madrid didn't win the championship last year, despite having so many star players. Mbappé and the other players need to focus entirely on teamwork. Xabi has to orchestrate this.
It's true, if we look at Xabi Alonso's time at Leverkusen, he trained his players very well, and the teamwork between the Leverkusen players was excellent. It's true that Leverkusen doesn't have as many star players as at Real Madrid. We also saw that during Ancelotti's time in charge, before Mbappé arrived, Real Madrid performed exceptionally well, and their teamwork was excellent, ultimately leading to Real Madrid winning numerous trophies.
Since Mbappé's arrival, the number of star players has increased, and it seems selfishness has become a factor, making it very difficult for Real Madrid to win. Now, there's no other way but for Xabi Alonso to manage everything so that the players aren't selfish and prioritize Real Madrid's victory over individual victories.
It seems like next season we'll see how Xabi Alonso develops his best strategy. Certainly, if Real Madrid's star players remain selfish, it will certainly make it difficult for Real Madrid to win trophies. Without teamwork, it's difficult for any club to achieve success.