Whenever I plug in a display to the “HDMI (3rd Gen) Expansion Card”, no audio device appears for the display.
This issue appears to be related to the AMD driver and not the expansion card itself (might affect DisplayPort and USB C DisplayPort), but further testing is required.
This has popped up for me way too many times, so I wanted to share my latest solution:
I went into “Device Manager”, clicked into “Sound, video and game controllers”, and clicked “Uninstall device” for all “AMD High Definition Audio Device” entries (do not check “Attempt to remove the driver from this device”).
The devices added themselves back and audio was working again.