[LawnboyMax]

This may be an interesting addition to some home assistant developed using https://www.home-assistant.io/

That is, use Google Home/Alexa/Apple Home for their speech recognition abilities while ensuring it doesn't eavesdrop and works with any other smart device that you have (e.g. there is no way to directly control Nest using Apple Home).

[kelnos]

There's really no need for that. Google at least has a speech recognition API that you could send audio to directly; no need to use a Google Home as a middleman if that's all you want.