I repeated the operation yesterday and since then it’s back normal. Even after another round of app updates
Mine is back to normal for now. I still don’t know what caused the drain and I don’t know why it is currently normal again. I didn’t do anything particularly besides keeping the installed apps up to date.
Maybe there were indeed some faulty apps, which got fixed with some updates.
BBS still shows 100% PowerManagerServices.Wakelocks (reason unknown, maybe Bluetooth or similar keeps it alive), but the heavy drain went.
I’ll watch it, of course.
Oh, and I cleaned a lot of cache a few days ago, using Cache Cleaner from FDroid. Doing that didn’t change the drain back then, but I think it is good to have back some more free memory space.
In the end the power consumption now seems even better than before the drain. Maybe also thanks to EnforceDoze, which I installed during the search for solutions.