Frontend URL: https://main.d1msjh4sev72n9.amplifyapp.com/

The current situation is as follows:

1. There is a Firebase controller in the project that isn't connected to anything. It should be removed after a thorough check confirms it is unconnected.

2. MongoDB currently handles all user data and identity data. This is a not secure enough; MongoDB should only handle data, while Cognito should manage the login and registration processes.

3. There is some missing logic with Cognito and Google authentication. After a successful login, Cognito sends a code to the backend. This code should be converted into a token in the backend and then returned to the front end with all the necessary data after integration with the database.

4. For the SNS service, all Gmail validation should be handled through Cognito and AWS SNS.