After fighting a long time to own my music, I have to admit I got tired of maintaining a library, and mostly listen on Spotify these days. But I never liked the library-based model anyway, and so (when still dipping into my own library, and especially when watching movies) prefer an app like VLC that accepts that I might occasionally just want to play a media file without making a library. (Same thing with Books: for some reason, Apple can accept that I might just occasionally want casually to open a PDF in Preview, but finds it impossible to believe I might want to do the same thing with an ePub. I still haven't found a good non-library-based ePub app for macOS; I wind up just using the one that comes with calibre.)
Thank you for the recommendation! Having to sign in is even less appealing to me than being forced to maintain a library, but it's good to have the option.