If you haven't looked into this already, I'd recommend checking out how to write a udev rule for your USB devices. There's probably a way to lock them down so OBS identifies them consistently.
The Arch wiki has fairly in-depth instructions for understanding how udev rules work https://wiki.archlinux.org/title/udev
This may also be helpful: https://wiki.archlinux.org/title/webcam_setup
Screen 2 will be running any apps I need to show (coding etc.) and screen 3 is at the back of the workbench, which has a downward facing camera so I can show me working on the boards and other electronics.
Switching scenes from main cam to what's on screen 2 to the workbench is very handy, even without a dedicated key pad.
The only hassle is that under Linux, OBS sometimes forgets the camera device designations on startup and I have to pull out the USB connections, re-plug and then go into both camera definitions and re-select the right cameras.
I have device video and audio sink definitions behind he scenes so that the video and audio can be fed to virtual devices inside Zoom or Teams etc.
Edit: Oh, and I have a client plugin which allows me to use my Android phone camera as a roving webcam to highlight things on the workbench such as a scope screen, power supply current reading etc.
All works quite well.