Right, so... (All this is on Mac, Big Sur, Snap Camera fully updated)
1) I can see myself in Snap Camera app.
2) Snap Camera isn't listed as a source in Google Meet in Chrome
3) Snap Camera is listed in Google Meet in Firefox, but it just says "camera is starting" if you try to select it. If you've had a different camera selected first, the preview/image just freezes.
I have tried clearing the caches, I have reinstalled. I'm pretty much out of ideas at this point. Anyone got any other suggestions?