I'm all for calling Bayern coaches normal haired frauds, but I think people should keep in mind how many things were wrong with the squad this season:
-Upamecano has been doing wild stuff all season
-during last winter Kimmich caused a lot of disruption with his vaccination refusal and basically missed an entire month
-after Kimmich's return Davies, someone he didn't really have a replacement for, missed four months with myocarditis
-around the same time Goretzka, who they have no proper replacement for either, also missed four months with a hip injury
-around the same time the management produced a public falling out with Sülinho
-Lewandowski working on his transfer
-the team taking some random Ibiza trip, completely undercutting Nagelsmann to the public
The Gladbach loss was inexcusable, but in general it's no surprise that defensive stability takes a hit, when both your starting LB and CM pick up lengthy injuries and you have no real replacements for them, all while your CB star signing produces one clown moment after another. Compared to Flick it's also worth keeping in mind that the latter got to work with Alaba and Boateng, whereas Nagelsmann got Upamecano for a replacement.