My previous report of a working Pulseaudio on a recent upgrade from Buster to Bullseye was incorrect. I'm not sure what happened. I rebooted my PC after the upgrade and was met with a GRUB rescue prompt. I reinstalled GRUB from a rescue CD and all appeared to be well. However, today after booting up my PC sound was completely broken. Games, system sounds, etc. The only sound that was emitted was a repetitive, low volume, distortion in all cases. I had to perform a system rollback to restore sound.