Sync progress online

[syt0r]

Backups can be used across different platforms so it's possible to make a feature for automatic backup uploading to a backend. Although it most likely will be a paid feature

[Anti-Apple4life]

I actually thought of something that would be free. If you could have the option to save the databases (kanji_data.sqlite and user_data.sqlite) to a folder using Storage Access Framework, you could you a free tool like Syncthing to manage syncing progress.