I was screwing around with this multiple C920 webcam thing today because bouncing back and forth was driving me up a wall. I was able to make some headway. I completely removed the entire Logitech Webcam Software package along with the drivers. I plugged in a camera, and through the device manager, I “updated” the driver to use the old Generic USB Video Device driver.
I can now use the OBS right click -> Properties and configure each camera independently inside of OBS. I’m not sure if the settings persist between reboots, disconnecting the cameras, etc, but at least they are all able to be managed from inside of OBS independently.
Not sure if that helps anyone or not, but it makes my life a little easier.