PCM2902 device not visible as input.
Device in question: Behringer Xenyx302USB using PCM2902 Audio Codec
Device would connect and be visible as sound output only. Input is either empty or shows list of the other connected devices.
Solution is to edit /lib/udev/rules.d/90-pulseaudio.rules
and comment out the line ATTRS{idVendor}=="08bb", ATTRS{idProduct}=="2902", ENV{ACP_PROFILE_SET}="behringer-umc22.conf"
It looks like problem is caused by wrong configuration. I tested this with Pop!_OS 21.10, Pop!_OS 20.04 LTS, and Manjaro GNOME 21.2.1 with the same exact results.
I'm currently on Pop!_OS 21.10 with pulseaudio 15.0
From my searching it looks like that this problem is on most devices that use PCM2902.