What if you select the webcam? Does that give you the OBS VCam?
I've seen things get swapped around before, with two lists - hardware paths and user-friendly names - that need to be kept in sync and they're not always...
I fixed it on my Linux machine by copying the line from OBS's source code that sets up the VCam, and only runs if it's not already set up, and pasting it into a script that runs when the system starts. So it's *always* set up as far as OBS sees, and it just grabs that. Then I tweaked that line in the script to make it #99, to keep it away from the automatic #1, #2, etc. that correspond to physical devices.
How to do that on Windows, I don't know, but maybe it gives you some insight into what might be happening.