I have a similar problem with this, but it is weird.
I got a new Razer cam to replace my AVerMerdia camera. When I port the camera through OBS, I can see the red box, but I can't expand it to the extents of the available image. I can shrink it, stretch the image, rotate the image and reset it, but I can't move that box or expand it to get the full image available.
I don't know if this is because of the available resolution being higher than what it can handle or what.
Interesting thing, though, when using OBS to port to Zoom, I noticed parts that were not in the red box. So I am wondering what is going on there (and no, I am n ot using the camera directly to Zoom...).
It seems I can move the image around, but I can't drag it or the red border so that I get what I want to see on the stream.
Any clues?