Crisis averted; after few days of working on second PC, I was able to find some time to smash `apt dist-upgrade` and `apt upgrade` until everything was updated to the latest versions.
Because Snaps still suck and I need Firefox, I installed it from Flathub and added symlink to ~/.mozilla (who needs sandboxing anyway).
For now everything works quite stable, but after this... incident, I guess I should prepare for distrohopping again... nah, I'll just migrate to Debian and Flatpaks.
@esheep The only proprietary driver I use sometimes is for Datapath VisionRGB frame grabber (which wasn't updated for latest kernels yet), so I have one less worry.
Last time I was using Debian with KDE it was stable, but back then it didn't had all QoL changes which were added in newer versions.
I need to check which proprietary software I actually need for my projects, maybe I could move everything to containers and switch to Alpine Linux in the future...
"I appreciate SDF but it's a general-purpose server and the name doesn't make it obvious that it's about art." - Eugen Rochko