Check out qpwgraph: https://flathub.org/en/apps/org.rncbc.qpwgraph

It’s like Helvum but it can save patchbays and restore them on boot.

The easiest solution is to create a virtual audio device through your Pipewire config and then use qpwgraph to link them up to your physical device on boot.

I can copy my Pipewire virtual device config if you need it.

I have used this setup to separate game audio from voice audio when streaming for years.