How can I rebuild my Apple Music library on iMac?

I am moving away from using Dropbox, where I have stored my music media. I have copied everything to another cloud service, and have discarded the former Music Library.musiclibrary. I have renamed the former path to my music collection in Dropbox. When I look in ~/Music, it has recreated the .musiclibrary, using a name I previously modified it to in my attempt to get rid of dependence on it.

When I open Music it has all the previous information (artists, tracks, ...). My intention is that it know none of this and that I rebuild the library from the new cloud service location. When I open a track, it says (appropriately) that it cannot find it and offers to locate it. If I locate it in the new cloud service location, that works - but I have thousands of tracks. There must be some way to rebuild the library from scratch. I tried deleting Music to reinstall it, but the OS will not allow me to delete it.

Help please

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