OOKKKK! It looks to me as if there are 2 [or more] ways to use a separate library, one is 2 [or more] separate sources, slave/not slave, as used by the OP, or my library and your library. Another is using a separate library, basically, as a switchable backup [with some restrictions] to a similar/same library.
Dell Latitude 13.5" 2-in-1 Ubuntu/Win 11
Samsung Note Pro SM-P900 12.2 Android 5.0.2
Samsung S7+, Android 12
Samsung Note Pro SM-P900 12.2 Android 5.0.2
Samsung S7+, Android 12