Thanks for the details, Philip.
Given what you have described I suggest you try replacing the Windows Camera app with OBS first. Quite a number of us, myself included, now use OBS with a webcam and Audio Interface to make our videos. You can download it free from https://obsproject.com/
You’ll find a lot of details how to get going with OBS in this topic. Using OBS with an Audio Interface on Windows for streaming to send to Zoom
OBS has a built-in noise gate filter that would be simple to use.
I think worth a try and all it cost will be a little time.