Just made a video of a workaround that uses a free bit of software (VoiceMeeter) to mirror audio on Windows.
"Oculus Quest Live Link audio mirroring solution" on youtube (sorry can't post links).
1) install the software,
2) set the new virtual audio device to default audio output
3) set oculus "device" settings to use "Windows Settings"
4) Run VoiceMeeter and set up your Oculus headphones and your PC output as the two outputs.