The problem was not firebase. The real problem was to use the platform as a silver bullet.
GCP have a lot of resources that you can use to meet the needs that you mentioned in your article.
Only as a feedback, study a GCP architect certification or any other cloud certification and use the services that cloud provide according your needs.
If you don't choose the tool according the needs, today you have the problem with the service, tomorrow with the cloud, after that a problem with the language etc etc