Had a DLink camera like that
I have a couple DLink cameras that instantly freeze as soon as any motion happens in front of them. These Amazon cameras seem about as reliable.
This was a dumb idea from the start. How many people have security systems in place which would prevent this from working? Or pets that could potentially get out of the house if the courier isn't paying attention. Lots more things can happen too.
I like the other poster's idea of just having a self-locking box outside the door for any packages. Drop them in, close the lid and it's locked.