any idea of the port required for the AppleTV integration?
I give up on the AppleTV integration a while ago, since my AppleTV is on a different VLAN than my Home Assistant.
I tried to allow traffic from AppleTVs IP & ports ,1235000,7000,7100,62078 to Home Assistant IP & all port
and Home Assistant IP & all port to Apple TV IP & ports ,1235000,7000,7100,62078 but that didn’t work.
You need to set up an mdns responder/relayer for it to work as everything revolves around dynamic ports in zeroconf (only some protocols use fixed ports). You will get problems with the Companion protocol though as it won’t work if the originating IP address is from a different network. Some people have solved this with NAT, but it’s non trivial.
Add an interface in Home Assistant residing in the other VLAN is the best solution I would say. At least would be as I don’t know how easy that is (at least with HassOS).