I think so too, and I believe it's due to the numerous injuries, but Xabi Alonso won't be able to make Real Madrid much stronger in his first season. Xabi Alonso isn't a coach with experience in major competitions with high pressure, so that will have a significant impact.
In the Champions League, everything will be different. The competition for the title is quite fierce because every team is ambitious to win the UCL. I think that's the reason.
Xabi alonso was completely successful with Leverkusen we know. But with Madrid, the scenario could be different. Alonso is very talented, no doubt about that. However , it is quite difficult to manage a squad with so many star players. Alonso has no previous experience of managing such a squad.
I believe Xabi Alonso will be successful. But it will definitely take some time to stabilize this squad. Dominating the Champions League and La Liga at the same time is quite difficult. If Xabi Alonso is given enough time, he will definitely be able to do so. However, it will be difficult for Real Madrid to dominate La Liga and the Champions League next season.