Looking for in-home intercom / audio braodcast solution

I’m searching for a way to have an interhome communication system. From what I can find, it seems 2-way audio isn’t really a thing in home assistant, at least with regard to video doorbells. From my searches, it seems google home has some audio broadcast features, but I’m not really interested in using anything google, or any other cloud service.

Basically what I want is something that resembles old school home intercoms, where a person can speak into a mic from one room and that audio gets broadcast somewhere else in the house. A primary feature should be that it not be two cumbersome. Ideally just a hold down a button and speak into a mic, like the traditional wired ones. Basically, anything that is more steps than just making a phone call is probably not going to be worthwhile.

Anybody have a setup like this? Or know someway to implement it?

I’m running hassio on a RPi4. There’s two of us in the house both using iphones. Communication primarily would be between one person sitting in the office, and the other probably on the couch in the tv room, or maybe in the kitchen.