Create a “goodnight” button helper. Expose that to google. It gets treated as a scene. In your google goodnight routine Add Action → Adjust Home Devices → check Adjust Scenes and click Edit actions → check the button you exposed. Again, it looks like a scene in Google Assistant, but it really is a button.
Add that button press event to the triggers in the automation you want to run.
Now when you say hey google goodnight, pressing the good night button in HA will be part of that routine.