There is a cheap doorbell that home assistant users have running that is made and re-badged under multiple brands including Hikvision, not sure if Openhab users have gotten onto it yet?
RTSP and snapshot work, but you can not get button push alerts unless u diy and hacked solution.
Edit: Found this idea…
Personally I am thinking of using a Dahua/Amcrest/ hikvision camera hidden up out of view that has alarm INPUT and OUTPUT terminals which Openhab can now control with the ipcamera binding. These relay terminals can be used to connect to any doorbell switch and buzzer/bell.
Result is button, audio and motion alerts direct to openhab and no cloud subscription.
Two way audio is not implemented in the binding but I suspect it can be done with Dahua and amcrest easily enough as the api has this feature.
Another brand which has an api is
https://www.doorbird.com/api