...
dtparam=audio=on
...
You, sir, are a scholar and a gentleman. Thank you.
One note, though, is that the file in my fresh 12.0.1 install has the following lines:
# uncomment to enable analog audio output
#dtparam=audio=on
#audio_pwm_mode=1
I will have to figure out the audio_pwm_mode effect. Probably by digging in the ALSA or PulseAudio docs, but maybe by experimenting.