Data file sharing between two applications

Most often, yes, this is the case.

Each app has its own sqlite database, this is not shareable with other apps, as far as I know.

You could use an online resource to store your sqlite.db, and import it to different applications as required...this will be a bit messy especially if you have multiple users....

You could also work with google sheets....

and I forgot to mention SAF (storage access framework)