Music Library Not Seeing Local Files

Recently suffered a hard drive failure. Mac is back in good health, but while the new Catalina music library is showing my full library with playlists & play counts, it's not seeing the local music files on my hard drive - it's only pointing to the iCloud Music Library version, which is far from ideal due to the number of mismatched songs in there (where the iCloud 'matched' song is different from the on-disk original) & these being DRM'd when the originals aren't.

Pre-crash, the Mac ran an earlier macOS version, which may be part of the problem. Any pointers on how to tell Music where the on-disk originals live & have the application properly recognise them?