apparently it’s possible without a relay look here

i had frigate running locally and could integrate them. That said i grabbed the stream from the local network. I guess you would need some sort of local pi to forward the streams. But that is well above my pay grade ^^ sorry

Reolink. Cheap, good enough quality, great HA integration, no internet connection needed.

just look for the HomeKit Bridge integration and expose what you want. I am running one bridge per device type (light,cover,sensor,switch…)