no doubt Nagel often uses Mane as a Finisher to replace Lewandowski's role, but it seems that Mane does not fit the position that Nagels wants. so Nagel had to rack his brain to change his strategy when playing his matches.
As a result, Bayern can't play at their best.
This goes to show how incompetent Nagelsmann is he doesn't really care about the players and what they think, and what they are capable of doing, not all players will surely adapt that fast to all of his strategies especially those not as skillful as Robert Lewandowski, yes Sadio Mane has the talent but he can not do all of it, he needs to adjust slowly, and he just recently arrives at Bayern Munich so he has a lot of adjusting to do and he can not properly do that in a small period of time,
I would not say that Nagels is incompetent. In this case, he doesn't put the players and what the players want. as with what you said, after all Nagels is the boss at bayern munich.
like it or not, the players must be able to professionally follow Nagelsmann's instructions. and if the strategy doesn't go according to plan, I think Nagels has figured out what the squad is missing.
After all, this difficult situation is the first situation for Nagelsmann during his tenure in charge of Bayern Munich, for the past year.
As for Sadio Mane, no one doubts Mane on the pitch. he is one of the top players who is shining, but his presence in the Die Bayern squad has not been able to show a brilliant performance.