Nagelsmann doesn’t need to worry too much yet. Bayern will probably still win the league despite their bad form. There’s only really Dortmund as a proper competitor & they have lots of young players who could choke as the season goes on. Bayern know how to win the big trophies, they have a lot of players with bog experience.
The problem is that with such an uncertain performance, Bayern could once again miss out on the Champions League title. Last season, Bayern also looked great from the start (and in the Bundesliga too) - they scored a lot of goals but also conceded a lot. The pattern is repeating this season, with Bayern risking get an inconvenient/lucky Champions League opponent and be knockouted early on.
Bayern will certainly pick form,but we can also assume that the absence of Lewandowski is now having effect on their team,because Lewandowski was so instrumental to the success of Bayern that they will continue to miss him at his absent.He was replaced by Mane whose impact is also now felt by Liverpool.I still think the league has not gotten anywhere yet for us to conclude that Bayern will not meet up this season,things can just change and they will start winning matches again and they will win the tittle again.