Why are you saying it's impossible to happen until 2026? Xabi can leave from the club anytime as he wants. There's no need for madrid to wait for him while ancelotti was still there. Xabi agreed to extend his contract but he will never forget that if madrid has become his best club. Leverkusen can keep him this season, but Madrid may want him next year to replace Ancelotti. Xabi just need to focus on leverkusen now. Madrid may come with a new offer for him next year. It will be so difficult for xabi to reject madrid's offer once it will be real. Xabi is still having a dream to coaching real madrid. As long as xabi shows a good result in leverkusen in the upcoming season. The chance for madrid to sign him as a new coach is big.
Yeah I agree, extending contract is never been guaranteed that person is going to stay until end of this contract it's just formality and Xabi can leave anytime when he feels not good at this club Bayer Leverkusen even his performance in first season was good, and now he can improve this as well with learning from his mistakes and as we all know Carlos Ancelotti is going to leave after end of this season then most chances he will also leave this club for the Real Madrid but still it's never been sure.
Currently, Xabi is just 41 years old and long career is waiting for him but if he has good opportunities then surely he needs to grab these right now his first target is having good results with Leverkusen which is possible because in last season we have good results from him while he brings this club from relegation to sixth spot and now things can go much better as well.