

Verizon and ATT just rebrand nokia ONTs and roll some of their own software that is mostly enhanced or changed encryption at L1. Can’t speak for Comcast, I only know about the other two as I’m in a smaller ISP that competes with them.
They use have L2 onts that don’t have any gateway functions, just fiber to ethernet with some extra overhead to monitor the connection between the hose and shelf.
The ONT-on-a-stick units do the same thing, just a more compact and expensive interface that doesn’t have great support, unless comcast or running all home run fibers where they can just provide a straight SFP instead of doing any optical splitting.
I use Frigate and HomeAssistant, they are on different hosts and the only port allowed from Frigate to HomeAssistant is the non-auth api port. For normal users using Frigate, I use an Oauth2-proxy instance on the same host (same compose) as Frigate tied to a third host with keycloak. go2rtc is on the Frigate host, but it only talks to Frigate and the cameras themselves. You can also access go2rtc from outside if you want to access the streams directly but your HomeAssistant does not need too. I find that this is better than the cameras directly as the processing is not really meant for a whole bunch of streams at once.
I followed docs for the HomeAssistant to Frigate stuff with the GIF notifications and it is working fine. I also use the Frigate integration (using HACS) so maybe there is a lot done for me.