You can get a wireless doorbell for $25 which will require no permission from any reasonable property owner.
Seems to me a QR code removes the $170 bit that was a key part of the Ring camera value proposition.
And for people who do not live in high-crime areas, but might want the other features of a Ring camera, the value distribution would necessarily be different.
https://www.honeywellstore.com/store/products/portable-wirel...
I would look for something like this: https://www.honeywellstore.com/store/products/portable-wirel...