Idk if this covers your needs, but Home Assistant is non-cloud and supports voice commands. They're selling a voice hardware now (preview edition):
https://www.home-assistant.io/voice-pe/
While I've used HA for years, I've never tried any of the voice command methods, so can't really comment on it. I had just recently came across their voice hardware and am probably going to give it a try.
It is. I remember reading it in a guide (pretty sure the one this screen shot is from as it looks very familiar). I was able to do it a couple times, but it required enough precision / luck that it wasn't worth doing IMO.