I have got some questions regarding Google APIs (Firebase, Drive and Smart Lock).

Hi guys,
I have got some questions regarding Google APIs (Firebase, Drive and Smart Lock).

I am trying to figure out the best way to store user sensitive data on an Android application (as sensitive as bank data).

I do have some requirements on my side: the user must be logged on his Google account to retrieve and save it. I should not have access to the user data outside the application and without his permissions (I don’t want an unencrypted access in a database console like Firebase for exemple), and I also need to have access to the original data (which means no hashing). The user cannot have access to his data outside my application.

-> Smart Lock is good but the user can remove it and read the data outside of the application.

-> If we store the data in Firebase Cloud Firestore, every admin of my project will be able to access the data in the console.

-> I also thought of using App data storage in Google Drive (which respect all my requirements) but according to the documentation this feature will not be supported in the future.

Is there another way to store data like the App Data Storage (user private storage, read & write only within the app)?

Thank you for your help.