During his playing days, Alonso was known for his exceptional passing range, vision, tactical intelligence, and defensive abilities. Thats why i believe he make a good journey for real madrid.
But in my opinion Alonso is not ready to train big clubs like Real Madrid and he needs a more mature experience in Leverkusen at least one to two seasons, so he will get used to facing pressure while undergoing big matches like in the Champions League. Although the quality of Alonso does have the ability to manage strategies, tactics that can perfect players and the ability to survive amid pressure from the opponent's attack, but it is all not enough and there was a lot of pressure when a young coach came to Bernabéu
Handling clubs that have a long history and many star players in it will be far more difficult than training ordinary clubs. This challenge is what Alonso needs to prove, at least he must be able to bring Leverkusen to finish third in the next season so that his chances of training Real Madrid in the future are wide open.