The progress that has occurred while Xabi has been at Leverkusen has indeed made a lot of progress at the club. And this season is their best season in performance, in fact their performance is almost perfect. Currently, Leverkusen can be said to be a club that is very on fire and can also make changes in the Bundesliga over the dominance of Bayern. Yes, although we still don't know whether Bayern Munich will soon take over Leverkusen or not. because unfortunately, there are rumors that Xabi and Real Madrid have reached a personal agreement. but whether this will come true or not. If so, then of course this will have a big influence on Leverkusen.
It seems that everything is just a rumor that is not yet clear because there has been no official statement from Xabi or Madrid. But if they have agreed, of course Xabi must give the best results. At least Xabi can give good memories with the Bundesliga champions.
I think Leverkusen will also immediately look for other coaching options to prepare if Xabi leaves. Because they also don't want to keep Xabi. There is no clause of any agreement, but it seems that Leverkusen supports Xabi to develop. Leverkusen will provide a clear door and discussion if Xabi moves.
Not convinced by these rumours regarding Xabi joining Real Madrid. Until an announcement, its speculation. Given Xabi's Leverkusen contract's specific clause that allows an early termination if Real Madrid comes calling, its not impossible. Based on his recent performance, Real Madrid may be considering Xabi to replace Ancelotti.
Leverkusen appears realistic about keeping Xabi. They're probably considering other coaches. Given their current success, Xabi could lead them to a trophy this season, a fitting departure. I dont think Xabi is Key to Leverkusen's success. They've got a good team and can succeed after him.