pacmd only works on PulseAudio
But pactl works on both PulseAudio and PipeWire
To show all available sinks
pactl list sinks short
To show default sink
pactl get-default-sink
To change default sink to another sink NAME
pactl set-default-sink NAME
The sink number can also be used in PulseAudio but the sink order and numbering is mutable
Internal devices do not change pci location code, but a USB device would change name if plugged in to a different USB socket