Xabi Alonso has proven that he can build a team with even strengths across all departments when he was coach of Leverkusen, so I think he could do the same thing again with Real Madrid in the future.
At this point, we can't make any judgments because Xabi Alonso is new to Real Madrid and still needs time to adapt.
Regardless of who Xabi Alonso chooses, I'm quite optimistic that Xabi Alonso can make Real Madrid even better.
And it's also important to remember that Real Madrid are the Champions League champions, so they must remain a force to be reckoned with no matter the circumstances.
As long as no player lets their egos dictate, like "I'm the star player here," Xabi might be able to strategize effectively, as he did at Leverkusen. However, if they play with their egos on the field, it will be difficult for Xabi to get Madrid to play solidly. They also still need to adapt their strategy; if any player plays with their egos, it will take Xabi longer to improve Madrid.