This is not a helpful answer and I do not know why it is endorsed by Apple.
First off, you don't need an internet connection to use the camera. Secondly, the user said they just bought it BRAND NEW.
I will second that its not the case that its due to internet connection or to it being dirty. I just bought a 2020 Macbook Air. Via facetime over internet connection OR through photo booth and through Zoom settings camera before I even log into a meeting, the video is grainy, dark, like I'm looking in the camera of an Iphone 3. I compared it to a 2012 MACBOOK PRO!!! And the Macbook Pro from EIGHT YEARS AGO is way better quality. As another user said, it is like NIGHT AND DAY. I will likely return or exchange mine also, this computer has been nothing but problems. Apple no longer cares about quality and functionality. They only care about profit.