I'm aware that Google assistant integration will arrive with Kodi 18 "Leia" but I thought I'd give it a shot anyways.

What I did:

I have an old Linux atom PC running on my network, so I wrote a quick .net core webAPI app to run on it hosted via nginx and some reverse proxy forwarding to the web app.

The app basically has various http GET actions in the controller that , when called, make a JSON RPC post call to the corresponding IP where Kodi is running (there are alot of guides on the Kodi web service api). It's helpful to set up a static IP for your android TV.

Next, add a NAT service routing rule so the Linux web app is exposed. If security is concern then limit it to HTTPS with a self signed cert.

Also, subscribe to a dynamic DNS provider if you can. I have a Synology NAS so I get that for free (*.synology.me)

Downloaded the IFTTT app and created a new IFTTT applet. the "IF this" step will be google assistant and what you want it to respond to e.g. "Kodi uptairs pause".

The "then that" step will be to launch a web hook. A web hook is an http call (get,post,etc...) Where you specify the method ,url, and optionally a request body to submit.

I can now pause/unpause movie playback in Kodi via Google home speakers :)

Keep in mind that you need to enable Kodi web services to do this, and Kodi needs to be running (it will still respond to events when in the background though).