Why does Apple Music on MacOS Monterey not recognize local files?

I had my entire library duplicate the other day within Music so I decided to restore all my local files from an external hard drive.

I purchase music in .mp3 format, open it with the Music app, then it creates a local copy which I can back up for future restorations.

I deleted all my local .mp3 files, then copied over a backup I had from January 3rd, 2023 to the location they are saved locally on my iMac.

Here's a screenshot of where the 5,000+ songs are locally on my machine:

And here's where my Apple Music Library is set to look for them (the locations are the same):

Yet, when I open Music I have only 31 songs showing in my "Songs" list. If I turn Library sync "off" nothing shows in my Music Library; not a single song.

How do I get Music to recognize all of my local .mp3s (again, 5,000+) and add them to my Library so I can turn on Library sharing and get all my music on my phone again?