I doubt Ten Hag, not because he is a bad coach but the squad that Leverkusen currently has is not as good as Bayern Munich, especially since several of their key players have left the team, so I think realistically, Bayern Munich has a strength that cannot be matched by other Bundesliga teams.
You are right, I also can't trust Ten Hag. Last season was not good for Leverkusen, they couldn't even compete with Bayern Munich for the title. I even have doubts about the upcoming season. Ten Hag doesn't have much of a reputation and he doesn't have much of a track record. Last season he was linked with Manchester United where his performance was not good at all and he was putting Manchester United in a bad situation. Now it remains to be seen how he will do with Leverkusen, but I don't think Leverkusen will be able to do anything good in the upcoming season.