Bayer Leverkusen letting Xabi Alonso join Real Madrid this season and also selling some of their best players to other clubs this season, I agree that Bayer Leverkusen won't be a problem for Bayern Munich next season, and Bayern Munich will continue their dominance in the Bundesliga league because Erik Ten Hag needs to build up Bayer Leverkusen's squad to the level where they can be consistent in winning their matches and challenge Bayern Munich for the Bundesliga title.
Xabi Alonso's tenure has already ended, and the person we are expecting something from now is Ten Hag. His coming on board just makes everything go differently because every coach has their strategy, so let's wait to see what Ten Hag will come up with for Leverkusen next season, and since they have sold most of their players but let's see what ten have install for leverkusen so there is a lot more and we know the kind club that bayern Munich is, so leverkusen needs to prepare there self for next season.
Because the next season is going to be tough, as we talk about Bayern and Dortmund, we don't know what they are currently cooking, so Leverkusen needs to tighten their belt if they want to go far next season, they need to work hard.