Thank you. This was very helpful.
I was able to get the matrix voice working with rhasspy + home assistant via MQTT using rhasspy wake word or the on-device wake word, they both work. However, there is a very long delay between when i speak, and when the action occurs. The wake word works almost immediately, and the lights on the matrix voice turn green, but they stay green for 15 - 20 seconds (and the i can see constant voice data passing over MQTT) then finally the action happens in home assistant, and the lights go back to blue. In your demo it appeared to happen very quickly.
Anyway, this may be a rhasspy problem, or a problem with my setup and i will continue to troubleshoot. If anyone has any ideas let me know, i’ll post back if i’m able to solve the issue.