USB Type-C headphones detected on Catalina MacBook Pro with 2 or more minutes delay
I would start diagnosing the issue using the IORegistryExplorer available as part of the &quot;Hardware IO Tools for Xcode&quot;, which you can get at Apple's. If it shows up there but not in the System Preferences, I would hazard a guess that it's a driver issue. If it doesn't show up there, then I would think it's a hardware issue. Maybe also check the system logs for coreaudiod; the USB audio interface I use shows up within a second of being plugged in and prints all kind of info there.
In general, I've never had issues with USB audio devices on macOS over the last 15 years, and this reddit thread indicates that there are others with a similar issue with AKG headphones. You may just have made a bad purchase - which shouldn't be too bad if AKG still pretends to cater to professionals.
Best of luck!