There's a large and growing number of music players for streaming from your own server. You get the best of both worlds by owning your music and having it accessible anywhere.
None of the OSS media players come even remotely close to the UX of Spotify, and that's speaking as someone who has paid way too much for Roon because it's at least 80% of the way there.
I've really been liking plexamp on my phone & desktop. It's not perfect & I've recently swapped to just using an iPod but it was good while I was using it.
