It feels like music players are becoming a thing for old geezers, like everything that requires you to have your data on a local disk. The 'modern' approach is just streaming everything off the net, no local storage required. (I'm writing this as a disapproving old geezer, just in case it wasn't clear.)
I must be an even older geezer, as I detest all the late wave music players that became full screen things that load music from everywhere. I organize my mp3s into folders by genre, then named by artist - title. To play one I double click it from the system file browser, and just want a tiny, og winamp style player to open and play that one song. Or multi select for an instant playlist.
I've never found a playlist editor better than Winamp. Open a folder tree of all of my music and I could quickly enqueue an hour of exactly what I wanted to hear and if that changed, swap in a few tracks, or an entire album or act from a folder. It took a long time to build up my library and I knew it very, very well.