The new SDK for local integration of google assistant devices with home assistant hubs came out 2 days ago…
from the link above:
The Local Home SDK enhances your smart home integration with the Google Assistant by adding a local fulfillment path to route smart home intents.
Integration of the SDK offers performance improvements to your smart home Action, including lower latency and higher reliability. Local fulfillment is supported for all device types and device traits, except those that use two-factor authentication."