This is not really a support question, more like a "what the hell happened"-question.
I had an adventure with old GTX1050 I tried to boot my HTPC with. Didn't manage to get past systemd, no failures, no errors, it just hangs before SDDM. Then I had a wise idea to preinstall NVIDIA proprietary drivers before I put the GPU in. Didn't manage to boot with that either, may be wrong driver version, I don't know and I don't care at this point. With all that hassle I'm content with my RX550 🙂
Anyway, since the proprietary drivers were installed I couldn't boot with AMD GPU either, so I had to proceed flashing a live USB and booting with that. Carefully following the boot rescue instructions at Help Center, I decrypted and chrooted to my system. The only mishap was that I mounted /dev/SolusSystem/Root instead of /dev/mapper/SolusSystem-Root, but that shouldn't make a difference as far as I know.
When I chrooted, I got an error message
cannot find name for user ID 0 and the user name was "I have no name!". I proceeded to
eopkg history -t anyway. I'm a reckless human being.
After rebooting I got to SDDM, but couldn't log in to my user. Invalid password. Huh, seems weird. After more thorough examination I noticed the user is absent on /etc/passwd. While the home folder is intact the user is just gone.
Afterwards I've created a new user, migrated the home folder and reinstalled all packages to be sure. I'm still puzzled how did I proceed to delete the user at any point? Could someone wiser enlighten me what happened?
TL;DR Use AMD