I use a Netatmo Presence outdoor camera that's mounted in the apex of our porch roof. Its been great so far. No storage costs, the device notifies you when there's detected movement in a target area that you can define, and it can tell the difference between people, cars, animals and other and you can set triggers accordingly. It has a built in flood light (bit weak over longer distances TBF) and IR, you can choose which one you use and how bright the light is.
You can also use the trigger event to set off workflows eg using ITTT or siri shortcuts - so you could make it a bit like a doorbell except obviously it wouldn't be able to discriminate between someone who actually wanted to get your attention vs. someone who is just posting something through your door!
The other thing it could trigger, I guess, is Sentry mode on, of course you can set parameters like times of day to do that, etc.
The unit itself houses an SD card and it saves the videos online, for free, plus you can also connect it to Dropbox or a home network storage via FTP (which is what i've done).
It's wifi connected but it does need power, so they suggest putting it in place of an existing security light, or as I did just dropped a new line in for it.
I've been really impressed by it
