Nice one! I have Google speakers and like the sound quality. Only annoying thing is that they can only be used with Google's cloud assistant.
After migrating to Home Assistant I have also created a HACS integration that uses ESPHome-based mics for the STT and sends the TTS to the speakers (works for any smart speaker exposed to HA):
https://github.com/bigbabol1/HomeAssistant_mic_to_mediaplaye...
Maybe I am going to try to capture the mic readings from the speakers to skip the additional ESP devices