I’ve found that generally if a device makes your camera appear as a webcam, ie: it works with windows “camera” app or a video chat app, it seems to work with unreal I assume this is because it has windows media/direct show compatible drivers. I think this explains why a lot of USB devices work ok.
I think the reason a lot of other devices don’t work is because they don’t have these drivers and need custom support in unreal or any other app to use them. I have a couple of avermedia capture devices (one USB and one PCI) that don’t seem to be recognized by any software except what comes with them.