Can I use Firebase as a backend that can provide offline local capabilities?

[Nikhil Krishnan]

I have been working on a project using Flutter and considering using Firebase as the back end. My use case can be explained as follows:
One user installs the application and wants to use it offline. The second user wants to connect to the Internet with Google or Apple authentication and wants their data synced across multiple devices. The application involves creating image files and managing different projects. Will I be able to use the NoSQL database provided by Firebase to create a DBMS for use in both cases? If cloud functionality is needed, like in the case of the second user, can the local database created just be copied up to the cloud?

Would it be a better solution for me to use a local database that can be used offline and then use Firebase to sync the data of this local database across multiple devices? What might be the limitations of such an approach?