Yes, it sounds like the pub/sub api was the missing link - commands function when run, but rules that trigger on events never ran becaue the events were not received from Google. If you run into any other issues, don't hesitate to post - there is also a lengthy thread for the App/Drivers that you can search through for tips: [Beta] Google SDM API - Nest integration
The pub/sub has 2 sides, in the Device Access project, to enable the topic to publish the events in Google Cloud, but also in the GCP project, to enable the API so that the Hubitat App can create the subscription (telling Google how to send those events to your hub)
