Recommended and mentioned products
Application and Data, Application Utilities, and User Management and Authentication
4) If you're building a strictly GUI application, consider using Firebase Auth for authenticating your users (i.e. The login screen). This takes away the pain of having to manage a database of usernames and passwords your self, and gives you really neat addons such as "login with Google" buttons/logic.
Bringing serverless to containers
First, reconsider your stance on containers, and consider using Cloud Run. Think of it as App Engine, but with the simplicity of containers. You'll have a much easier time using GCP if you go down this path.