I don't usually recommend software that isn't open source, but MusicBee is really great for organizing tunes. You can build really deep auto playlists based on any tag you like, you can do bulk updates across lots of fields, you can have it reorganize files into folders around any of the tags, including with fallbacks for missing tags, there's configurations to download metadata from online, all kinds of stuff. Plus it's a super customizable music player too.