Join Together can create a single audio file from the two or more audio tracks you drag to it, from Music, iTunes or the Finder.
This latest version is for macOS 10.12 and later (including macOS 10.15).
M3Unify is a file utility that helps you manage copying audio files to a folder, drive, thumb or SD drive, ostensibly for use with portable and car audio devices.
This latest version is for macOS 10.14 and later only. And it, too, supports iTunes 12 and Music in macOS 10.15.