I've seen "spyhole" cameras. So instead of the lens to look through on your door, it's a camera, with a viewer.
In a way lots more secure, as sometimes when turning g the flap to view out, the person can see light/shadow, and know they're being watched, or that someone is in.
With the camera method, there's no "tell", so they won't know. This has got to make it more secure. Trouble with cameras in hallways in apartment blocks, is some can contain you know their comings/goings and is a breach of privacy. However, a door spyhole camera only captures those coming to your door.
I've even seen in shop/store fronts where they publish a "statement" saying they're only filming for security n no picture is held on a personal decice.... Something along them lines.
In my situation, I'd have captured the fker who stole my powerbank.... No proof, but swear it was someone in the block.
So eufy, if you're giving anything away like this.... I need please.