For the record, I have a Surface Pro 7 (not the 7+). I never saw any updates about firmware updates for this older system in this chat, but I was on a Zoom call with a client for two hours on 1/19/24 without the camera failing. Admittedly, I was screensharing most of that time, but my camera still registered when I swapped back when I was done sharing, and turned off as it should when I ended the call.
This is significant progress, though I'm a little wary of celebrating, given how often this bug crops up. So, possibly the problem has been solved on the Surface Pro 7 (and without having to do anything on my part).