Pass Through Mask Material

Hey y’all!

I am having a heck of a time creating a mask material to hide parts of my AR mesh. In the attached image I want everything with the red material to be the camera view. Clearly there is a camera feed I should be able to attach to a texture and world align in order to achieve this affect but for the life of me I cannot get this working.

The Get Camera Texture Docs seems to be removed?

Enumerate Video Capture Devices is returning no cameras from the device either Docs:

Here is my material setup, I just need to replace that CameraTexture param with the devices video feed:

Seems like this should be a pretty simple task to accomplish but I am struggling hard, any ideas or input are greatly appreciated!