That worked! Thank you so much.
I went from 6.1 to 6.6, and that took care of it.
Previously I had to go from 6.6 to 6.1 because on 6.6 booting sometimes hung at the “three dots” animation. But I don’t reboot very often, and having to re-reboot after a hang is something I can live with. Besides, I still have the uninstalling of plymouth I could try (which may fix the hang, per linux-aarhus’s suggestion).
Merry Xmas to you too!