We have Google Home Minis in every room and the screens in bedroom and kitchen and the only thing that works reliably to message intra-room is to say "Hey Google, broadcast message" because half of the time it will tell me it can't send messages yet. If someone knows what I'm doing wrong I'd love to hear it since this would be a great feature.

To be honest, I'm honestly sick of Google Home's approach to this since the Gemini update has turned everything really slow and I'm getting close to the point where I'd rather home-roll a full system myself that works reliably instead of the crapshoot that this is. Home Assistant seems to have a functionality bridge to Google Home connected devices like my blinds or cameras so I should be able to retain the edge devices but I have half a mind to just dump the whole thing and start over.