The job is really difficult for Xabi Alonso because he is managing players that are rich and influential on one part and a remarkable team that is accustomed to winning on the other part. Xabi will have a hard time being fulling in charge of the team due to the rivalry and ego in the players especially Vinicius Jr and Kylan Mbappe. If I were the coach, I will bench them a couple of times so they can come down to earth and give their best. No matter what, I still believe that Real Madrid will make a great rival to Barcelona this season.
By the way, Vinícius is not such a simple player, and you definitely need to find the right approach to him. Especially now, with Mbappé's arrival, problems have started regarding Vinícius's salary. He wants to earn the same as Mbappé because he now considers himself an equally valuable player. But Mbappé’s salary is significantly higher than Vinícius’s, and that alone can already create some internal conflicts. I think Alonso doesn't yet have the experience to resolve such internal issues, but he needs to learn how to deal with them. And he needs to learn quickly, because if misunderstandings start within the team, it will definitely affect the results.
At the Club World Cup, it was clear that Xabi had a tough task integrating Vini and Mbappé together. When one of them wasn't playing, Real Madrid performed quite well, and Gonzalo Garcia even finished as the competition's top scorer.
Mbappé and Vini each have their own egos; they see themselves as key players. It was a tough task for Xabi Alanso to bring these two players together. The problem, as you mentioned, was Xabi's lack of experience managing a star-studded team. After losing to PSG in the Club World Cup, it was clear these two players couldn't play together. If Xabi can't resolve this issue, Real Madrid will struggle to compete in La Liga next season, let alone the Champions League.