> What factors made you choose Google Drive for syncing? And was it easy to set up?

Using Google Drive as a database is not easy to implement, but I chose Google Drive in terms of data ownership. The users can delete the data by themselves if they want and the app can't connect users' data without receiving the HTTP request from the user. These points are good for privacy laws and reduce the security risk.

It also keeps infrastructural costs low. It's also an important factor in providing the application free of charge.

The bad point of Google Drive is high latency, but the latency issue wouldn't be a big problem because the HTTP requests/responses wouldn't block user interactions in this app.