Music App Changed Preferences & Lost ALL Playlists—How do I return to previous settings?

Thank you for your assistance! The most recent Music Library I had available was one dated May 1, 2020, but that one restored the majority of my music files and playlists. Since I have a clear date to work with, I can simply reimport any music I've added to my collection since last May 1st, because the files are still on the external drive. And since I had not synced my iPod since the Music Library disappeared, I can use the playlists on the iPod to help me rebuild the handful of them that were new or were significantly revised since May 2020.

Thank you again! I will have some work to do, but nowhere near as much as I would have otherwise had. . . .

After spending the last two weeks restoring and rebuilding my playlists (because while the songs could be added to the app the playlists couldn't find the files, and I had to manually connect each song in the app to its file in the Music folder on the external drive), the music library was entirely gone again when I opened the app tonight. I have never had this much trouble with Apple's Music app before, but ever since I upgraded my OS to Catalina, there has been one system issue after another. It looks like I will need to find a new music app to work with my iPod, because I can't count on Apple's Music app to function reliably, and I can't spend hundreds of hours every month to rebuild playlists that should never be lost in the first place.