On this specific topic I think it is relevant for others here to know. Since home assistant is quite big.
I do use the Hikvision DVR for recording.
I don't have storage attached to the pi or a Nas.
And one caveat of home assistant is that the onvif integration does NOT support h265.
So the DVR records main stream 1080p h265.
And the second stream 960p is h264 which the pi receives. This way the DVR stays off the web, and I can have live view on the home assistant app with the port forward.
I plan on doing object detection and telegram bot so I can get alerts with pictures, however I'm moving house right now so that will have to wait.