I won’t quote your message this time, because it will be easier to reply to everything.
So sharing network namespaces will not help you. I mentioned only as an explanation why you can’t have host network and container network at the same time. I didn’t understand your issue first, but in your case, it looks like the host network is required indeed.
I’m not sure, as I never had to configure something that needs to discover services automatically running in Docker containers, but that could require host network.
If you try to specifically search for “home kit connect to docker container”, you can find issues like this:
It is a long issue, and also old, but at the end of it, there seem to be a solution. They run an mDNS repeater in a Docker container. I didn’t read everything, but I think the suggestions they describe could help you too, so you can use the proxy, add homebridge to the proxy network and and access the UI through the proxy (if you want to allow external access) and and optionally you could have a gatus network if you want to allow health checking through a separate network.
The other solution could be what @bluepuma77 suggested with the host IP. If you want to expose the health check endpoint on localhost, you can use something like I described here:
I wouldn’t do that if the mdsn-repeater mentioned on GitHub helps.