Display 3rd party camera view in-game?

Is it possible to have a frame/window that displays the output of a GoPro or similar webcam in WMR? There is a Steam tool that uses the left HMD camera to do this. But the resolution is too low, and it only works with steam games. I want to be able to see my button box in MSFS.

Currently the only way to do it though OpenXR itself would be though an API layer that draws an additional composition layer (or directly on top of the already rendered content).

The OpenKneeboard application does something similar for drawing kneeboard overlays:

There is some writing on how it is implemented by the author here:

In Mixed Reality Portal, you can open any application then pin that window to VR, and it will follow you into MSFS. That should do the trick for you.

PS: This is a developer forum, unclear if your question is development of end-user support instead.