It's not just about having quality players at Bayern Munich, it's also about more games yet to be played this season so Bayern Munich in general still has a chance to catch up with some of the teams that are already top of the table at this point. After all, the number of points Bayern Munich has with several teams in the standings at this time is not so much that it is still easier for Bayern Munich to catch up.
I think many are expecting Bayern Munich to make a catch-up with the leader on the standing and that is Union Berlin, it is too early to say that Union Berlin will be the champion and the next to be like Bayern Munich, there are still a lot of matchdays to have and I think right now Bayern Munich might be readying some new formation for their certain players to be more familiar with, but if Nagelsmann still insist of giving the part to Sadio Mane, then the result will still be the same, but I could also be wrong here,
It's been busy the last few weeks when Mane left and was replaced by Mane but it was a natural thing because, as you said, every departure, especially for a player who has always been the focus of a club, will definitely have an impact and maybe with Bayern's current condition it's not impossible. some will think that this was the wrong decision to sell Lewandowski.
Lewandowski doesn't want to be in Bayern Munich anymore, and the one that decided to leave, Bayern Munich just complied with what Lewandoski wants, because it is not worth it to keep a player that doesn't want to be part of the team anymore, I think it is still a great decision now that Lewandowski is gone to the team, then they will realize their mistakes and what Bayern Munich truly lack because for me Bayern Munich is relying so much to Robert Lewandowski, and all of Nagelsmann's strategy was for Lewandowski,