All the football lovers actually missed the opportunity to watch Ancelotti and Xavi Alonso when Alonso and his boys was unable to win the Europa League. Else it would have been in the Super Cup that we will watch these two great managers. Champions League might not be the best place to see them meet because they might not even meet till is eliminated. Unless they are both on the same group. Without being told we are all aware that Real Madrid has the most complete squad for the next season Champions League. So should not compare Real Madrid as a team with Bayer Leverkusen, neither do we do that with their coaches they are in different classes. While Ancelotti is a legend, Alonso is pretty new in the industry but with the capacity to break and make history.
In the new champions league model, it was still possible they would meet even before the elimination stage, Ancelotti would have had the chance to get to go head on with xavi Alonso and I don't agree that xavi is pretty new to the game because he was a good player who's well experienced in football, and that could also add up for his advantage too, this ahs added to his capacity as you did mentioned with which be can be able to break records and make history which I feel he was about doing with Barcelona before he was then sacked, he could still get it done elsewhere hopefully.
Madrid is very prepared and the magnitude of the team currently is undeniably a huge one that we cannot deny neither can we underestimate their abilities but I still have some resentments about them because I have seen times where much is expected of a team because of their Perceived ability and they end up giving below expectations, this was the case at PSG few seasons back when they had Messi , Neymer and mbappe all in one team, some taught it was the season they were going to win the champions league but then they couldn't make it to the finals even.