Systems sounds played despite being muted (PipeWire, no PulseAudio)
Using Debian sid/unstable with GNOME Shell 40.5, I removed PulseAudio and only have PipeWire 0.3.38-2 installed. Despite having the system sounds muted in GNOME’s control center, they are still played. With PulseAudio installed, the sounds were correctly muted.
Forcing such a sound by for example pressing the left arrow key in GNOME Terminal, in the section Audio of the GNOME control center, the entry below quickly pops up.
PipeWire ALSA [gnome-shell]