It’s possible to augment the zeroconf config to add additional services, but it would be nice if the official mqtt addon allowed you to have this done automatically. The integration docs said it can be added to the manifest to have it automatically picked up but I haven’t tried forking it to see how that works. (but it also said that all integrations requires a manfest.json and the repo doesn’t include wone of those as far as I can tell so maybe the docs are outdated or I’m confused)
In my pervious smart home world I had a pi running a mqtt broker and it advertised it’s self as a service under _mqtt._tcp and all my ESPs would discover it so if I changed the mqtt server I never had to tell the ESPs about it. they would just pick it up.
I think this change would be well received.