Exactly, there will always be changes, but if the coach from Bayer Leverkusen still stays and is still the coach then there is a possibility that Bayer Leverkusen has the potential to become champions again. Because so far Bayer Leverkusen still has attacking techniques which I am sure are still being kept secret and have been prepared for next season's matches. Xabi Alonso will still make his best contribution to always bringing Bayer Leverkusen to victory again in every competition they participate in.
Yes, if Xabi Alonso is still at Leverkusen this coach will still do his best like this season but there may be a slight difference because we don't know the performance of other clubs next season in the Bundesliga, especially Bayern Munich with its new coach who wants to regain control of the title Bundesliga and Stuttgart have also performed well in the Bundesliga this season and finished in 2nd place and this could be a new challenge for Xabi Alonso next season, especially in conjunction with the Champions League international competition where the level of competition is very tight and usually top clubs prioritize the Champions League First compare the league itself.
But I think that with Leverkusen's good performance this season, winning all matches in all competitions is a good result and they only experienced 1 defeat and it is likely that they will continue their good record, currently many of Leverkusen's players are productive in attack as long as they still have Strong stamina and no injuries means they still have the same performance in attack and that can help the club. Hopefully Leverkusen doesn't sell anyone because if they sell players who have good attacking power it will affect Leverkusen next season.