This is definitely not optimal and would be a overkill setup, but OBS Studio + VirtualCam plugin let's you basically screencapture anything and turn it into a w

This is definitely not optimal and would be a overkill setup, but OBS Studio + VirtualCam plugin let's you basically screencapture anything and turn it into a webcam device. So if your python app can display a video feed, you can capture the window and show it as webcam (with OBS as overhead).