HA to trigger Google Assistant actions in automations

Please tell me if this is already possible, but I think it would make sense in this example situation:

Some company made a smart light for $5 but they don’t work with HA at the moment, but they work with Google Assistant. So you can do an automation in HA that uses the Google Assistant API, so when you press a button in lovelace for example, it will tell Google Assistant to “turn on the light”

You could literally make HA do anything Google assistant can do.
Here’s another example automation:

  - alias: 'Leave Home notification'
      platform: zone
      event: leave
      zone: zone.home
      entity_id: device_tracker.paulus
      condition: time
      after: '20:00'
      service: Google_assistant.broadcast
        message: 'Paulus left the house'

I’m not a programmer, but I have seen many other projects of people doing things like making DIY google speakers

This is already possible. Using the add-on available here, you can effectively create a localized Google Assistant within Home Assistant. You can then use that Google Assistant to do normal Google Assistant commands.