As long as you have enough memory (Raspberry Pi 4+) it's a great experince.
I’m about to buy some cameras and I’m thinking of just buying Nest and using https://scrypted.app to bridge to HKSV.
I feel its pain. I break down in direct sunlight too. Doorbells would definitely be tricky, as I doubt most people know the path of the sun over course of a full year. I'd assume that most people look at the sun at the time of installation (if at all) and think they are safe. They don't take into account that exact time of the year when you hold a staff in the correct location in the map room to locate the Well of Souls where the light will stream in at exactly the right angle to the lens on the camera to melt the internal senor.
Maybe feng shui is proven correct by orienting your front door to the north so your doorbell doesn't face the sun?
Might also be privacy
ONVIF has specifications/profiles for management, functionality, and codecs (S and T):
You can get onvif-compliant firmware for some of those, but battery-powered operation cannot be expected to remain practical, given what onvif focuses on.