Normally I expect Leverkusen to struggle initially when the season will start because a new coach coming to the club means that a change in the playing style and philosophy of the new coach so it will be difficult for the team to just start getting results when the season starts it will take time before the team will start gelling and getting results
The problem does boil down to skepticism, which I think is quite reasonable because with Ten Hag's previous track record, I personally am also actually quite risky to see how Leverkusen will be.
Leverkusen in these 2 seasons looked very good by Xabi but being left in this season by Xabi and some of their key players and replaced by Ten Hag will certainly give a big doubt in this regard.
I just hope that Leverkusen can remain stable in terms of performance and even if there is a decline it is not as drastic as before because this could be a belief that Ten Hag is not that good at coaching if that happens. It is also a testament to Ten Hag that he can really prove himself that he is not a bad coach.