Changes to your display configuration made in a Plasma Wayland session (e.g. monitor layout, resolution, etc) will not persist to SDDM. To make them persist open Plasma's System Settings and navigate to Startup and Shutdown> Login Screen (SDDM) and click "Apply Plasma Settings...". You will need to have permission to perform this action.
I've just been logging in upside down for a couple years. My monitor's vesa Mount is like 3 inches from the top for some reason so having it upside down is the only way I can get a reasonable ergonomic height
That's what timeshift and btrfs is for! Really though it takes like ten seconds to roll back and each snapshot only takes like 40mb. There's a pacman hook to take a snapshot before updating.
AUR is just incredibly convenient for me. I don't have to think about it, I don't have to track anything down.
If you're on spinning rust with a modern CPU, compression actually helps your read/write speeds quite a bit. It's faster for the CPU to compress/decompress then read/write less data because hard drives are so slow in comparison.
I'm going to go against the flow here and say BTRFS. It's stable enough to the point of being a non consideration. You get full backups using a negligible amount of storage. Even using it on Windows is easier than using ext4 with the winbtrfs driver.
Every micro-angstrom and so on.