That makes sense that the more smaller the camera, the less quality. I also read that the more smaller it is, the more it overheats which is probably why the first one I bought overheated and went dead.
I also found this: https://www.peephole-store.com/fixed-on-door/60-dc-1-cb-wifi-pb1.html
It's really interesting but absolutely no reviews. Anyone has any thoughts?