I use Audirvana with Mac Mini OSX 10.15.4. Since upgrading to Catalina, I note the new Music App but the music library still resides in the same place under iTunes/iTunes Music. All my music are rips or purchased downloads and I’m very careful with metadata correcting anything manually as I add them.
I use Album Artist/Album/ so that Artists or Albums appear in Artist order. Prior to the upgrade any artist that began with “The” would be appear under the letter of the next word. So The Rolling Stones would appear under R and The Smashing Pumpkins would appear under S and so on. The problem since the upgrade is that any artist name in Audirvana Library beginning with “The” appears under T. In the Music App itself, it’s fine. Something appears to go wrong in the sync between the folder and Audirvana.