Bayern have so many players injured, I'm not surprised they lost. I don't know if it would have mattered even if the squad was healthier though. Aside from beating up some cellar dwellers at the start of the season, Bayern have lacked that killer, finishing instinct. They dominate possession... at midfield. Their chances are so often needlessly difficult, and Kane is all over the field instead of hunkering down near goal.
Kompany may be the right antidote to Tuchel, but it's going to be a nailbiter to claim the Bundesliga this year. I don't see him being able to outcoach anyone, even if management spend 300 million Euros in the offseason (which, given some of the numbers around Wirtz I've seen, if that happens plus a few more players, it's possible).