There is no warning on the configuration page to suggest the sync was not successful. The Sync Entities to Google ‘button’ does briefly go red and perhaps that is the clue it has failed. A warning message would be better.
When it does fail you will see this error in the logs (Configuration -> Logs)
Guess you were not beyond that point . Glad you are making some progress.
The Google Home integration via Nabu Casa is really lacking in documentation. Two other items that bite me for a while:
temperature sensors in HA can only appear as thermostats in Google Home. And it appears that Google home does not think you would ever need a thermostat in the ‘backyard’ so no outside temperatures.
If you do something to get HA in ‘safe’ mode, my instance of HA will log me out of Nabu Casa. So when I get back to ‘normal’ HA running, I have to relogin to Nabu Casa.