I have an old soundblaster live + livedrive. With Jack, it can behave like a 16 inputs / 16 outputs multichannel card. I just have to select hw:Live,2 for inputs and hw:Live,3 for outputs. Not really easy to know who's who the first time, but it works.
With pipewire, I only have 2 inputs and 2 outputs for the same card.
(Screenshots of 'pw-jack qjackctl')
What can I do to have the multichannel config back?
Note: It didn't also worked with pulseaudio.