PCC4k/6k/ATEMmini not working on Meta Quest HDMI Link

A short intro - the Meta Quest 2/3/pro VR headsets have just got a new free app called "HDMI Link" that lets you input HD1080/60fps live video from USB-C UVC web cam inputs and view them ...
Imagine being able to put on a headset and have a private, full HD viewfinder floating in front of you, no matter where you or your camera was pointing. The Quest3 and pro have color passthrough so you can see the world around you, while you also look at the camera output...

However, for some reason the PCC4k/6K (using FW8.6) and ATEM mini pro do not work with the Quest 3... They work fine into my PCs, happily pretending to be web cams by using UVC (mentioned in some posts by BM staff) , displaying in all their 1080P/60fps goodness

So in the app documentation they mention it has to be a "UVC and UAC compatible capture card " also noting "that capture cards won't display video if the HDMI signal has HDCP protection enabled"- my question to the BM staff are those the standards the web cam output are matched to ?
Is there some adjustment in the camera/ATEM firmware that should be made or is it the fault of the software that Meta should take care of?
If any other Quest users have tried this and succeeded, please let me know, so I can find the fault with my procedure...
Obviously if someone wants to do this now, the workaround is to use the HDMI output from the camera/ATEM and buy a separate 1080/60 capture dongle (around $US20-25 online ) to convert it to usb-c... but isn't it already in the camera , just waiting to be set free...