Push notification from a user if not logged in

Is it possible in any way for a user that is not authenticated to send a push notification? I saw this recent post in FF:

https://intercom.help/flutterflow/en/articles/6156999-troubleshooting-push-notification-issues-in-flutterflow

The only alternative would be to use Anonymous Auth? In that case when the user then authenticates using google or apple, firebase would merge both users or will it be the same user and FF calls the right function?

Thanks!

Pablo