Catalina import Library.xml into music app?
According to turingtest2 on Apple Support forums, you might be able to import the XML using the 'Import Playlist' function.

The XML file is for third party support. The active iTunes library
would normally have been called iTunes Library.itl though in some
legacy systems the .itl extension might be omitted. You can hold down
option while starting Music (or TV) and then use the Choose Library
option to access an existing .itl file. You will be prompted for the
path to store a new music (or TV) library converted from the old one.
Alternatively you can use File &gt; Library &gt; Import Playlist... to
import an XML file, but that will lose date added information that
would be preserved by working with the .itl file. Either method should
bring in ratings and playlists.

https://discussions.apple.com/thread/250869304