It does look like the camera settings Zoom was using changed once the meeting began. I've experienced similar things. Perhaps a pre-meeting check gave me a rather narrow camera view, but in the meeting it became widescreen so that more of my office showed than I expected. Or maybe my external mic sounded good pre-meeting, but when the meeting started Zoom used the built-in laptop mic instead so that I sounded horrible.
I don't have an easy, settings-based solution for you. I've been told that Zoom is a complicated app that accesses many computer functions at once, so that this sort of thing happens sometimes. I've learned to pay attention and plan ahead: expect that the camera may show more (or less) than I anticipate, be ready to tell Zoom again which mic to use, etc. And with the camera image, I also try to be aware that what I see during the meeting may not be what other attendees are seeing. I've looked back at recorded meetings to find that my camera showed a wider or tighter image than was presented on my screen during the meeting.
This means that if you're using a bedsheet behind you and putting a fake background on it (one more complicated function Zoom has to handle), be prepared for the unexpected. It you set your camera up so that the bedsheet just barely fits in the frame, you're setting yourself up for an embarrassing surprise. Instead, begin by assuming there's an evil madman inside your Zoom settings who's trying to prank you. Adjust your physical space to allow plenty of room for it to work even if the Zoom gremlin conspires against you. That's all I've got.