When I was still mucking about with files (before the death of my NAS), I put them into nested folders by genre. Artists that don't fit into any prevailing genre, had their own separate folders if I had more than a little of their music.

I now use my notes app for the music collection, with links to online services. It's an outliner, so I still have the hierarchical structure as the basis — it's more involved now, with top-level sections like ‘favorites’, ‘music from my childhood’, etc. Basically, it's organized by the criteria that I use when I'm looking for an artist, album, or tunes (just like other notes are tailored to me looking for them). But also, the app allows tags for the notes, so I can list e.g. metal records from the entire collection. Can't really do that in the filesystem unless you put something like ‘#metal’ in the artist/album directory names, or use a file manager that can read id3 tags, like Total Commander.

MacOS supports tagging for files, but it's not portable between platforms, the tags might not be preserved by some apps when copying files, and idk actually how to search by the tags.