Hey bradfordspeaks,
We understand that your external webcam is no longer recognized in Zoom or other apps that use the camera for your MacBook Pro. To confirm, this also happens in FaceTime, correct? What happens if you disconnect the external camera, wait a moment before plugging it back in? You may need to wait 10-15 seconds for your MacBook Pro to recognize the external camera.
Does restarting help your external webcam show again? Log out, sleep, wake, restart, or shut down your Mac Restarting can seem like a simple step, but it can sometimes help. You mentioned you updated to macOS Monterey. Can you confirm the specific macOS Monterey version your MacBook Pro is running? If unsure, you can find that in the Apple menu () > About This Mac > Overview tab.
Take care.