Now, to the success part, so I can mark this as solved:
- I searched for the word “error” in the journalctl log.
- First error I found:
Process org.freedesktop.systemd1 exited with status 1
- This gave me a clue to find some more related posts. This one seemed particularly relatable, and it seemed to point to graphic driver issues. It was solved by reinstalling. I didn’t want to reinstall
- Check which version of mesa I have:
pacman -Qi mesa- 24.1.6-1
- There didn’t seem to be an issue with this particular version.
- Reinstalling mesa
pacman -Sdd mesa- Oh. OH. OOOOOOH. That fixed it!
Turns out, one of the things damaged during the failed update was the graphics driver.