I've had my Note 20 Ultra since early September, unlocked version purchased directly from Samsung on Verizon's network. Lately I've been noticing the camera will freeze up. I just have noticed it a few times when unlocking the phone I'll get just a black screen for a while. I've finally figured out it's the camera app being shown. When this happens, the camera app will show either a completely black screen with nothing on it, or a black screen with camera controls at the bottom that don't work, but none of the UI elements at the top of the app. Force closing the camera app has no impact. If I leave the app open long enough, it eventually closes on it's own. Sometimes it will give the error "you cannot use more than one application that uses the camera at one time."
It does this without using any other camera apps. I suppose it could be something with Snapchat, but I'm not sure. Force closing both does not help.