Problem with Zoom finding my external camera

hello - i have a problem, zoom will not find my external webcam (using a sony a7iii). it only allows me to select the integrated laptop webcam. this problem only occurs on my laptop, i can use my webcam on my desktop no problem. The laptop is a dell latitude and is running up to date windows 11 and the version of zoom is the latest.

I have tried adding camera permissions to zoom in windows - but the only option there is to add permission for the laptop camera.

The cable I am using is good and works fine on my desktop. I have tried deleting and re installing zoom and checking for latest firmware for camera and zoom. Any ideas?