The point here is that I think the Bayer Leverkusen team couldn't stop Xabi Alonso from making the move he made to Real Madrid because it's difficult to reject an offer with the biggest team in the world but the mistake they made was to start selling off their players when they struggled last season and couldn't get a trophy. Ten Hag is now the manager of the team, how he will do the magic to get the team working again I don't know but all I know is that they can't be good like when Xabi Alonso was the manager looking at the number of players that has been sold.
I have been saying that the success of a team depends on the coach and the squad he will choose and the management in being able to keep the same coach for many years. In the case of Leverkusen, they were successful, congratulations, but whether they will be able to maintain the success with the new coach is another thing. I saw this news about them:

EXCL: Jarell Quansah set to undergo his medical at Bayer Leverkusen on Monday, all booked.
Can confirm again buy back clause for Liverpool will be worth at least £60m and could even reach £70m based on add-ons.
Initial fee also confirmed: £30m plus £5m to #LFC.
https://x.com/FabrizioRomano/status/1938978302901002301I don't know how good the new signings they made are, that's something we'll see when the season starts, but in my opinion I see Bayern winning the title again, because Bayern haven't changed at all, they still have the same coach and more than 90% of the same squad, while Leverkusen will take time for the players to adapt to the coach and new teammates.