Home Assistant Assist & Atom Echo
Video example: https://www.youtube.com/watch?v=tYFCeJbJb4A
Description: GitHub - mirecekd/atoms-for-girls: M5Stack Atom Echo mic and Google repros as speaker with two Home Assistant Assists
MirecekD
How did you setup the dummy media player you are using?
I like the idea off google announcing the respond, and the input device (atom) being silent.
But I can’t figure out how you did 
Simple one - remove all speaker mentions from esphome config 
Echo will be silent, but finally you need to forward voice (x in function on_tts_start) to any of your media_player.
I am using dummy player and approach by @TheFes described here: Send picture and text to display on Google Nest Hub while sending TTS
More simple setup would be (if you dont have Hub) just send x to your homeassistant.service tts.xxx not to script as I need to.