I don’t know if you’re using debian but I encountered the same issue. The wiki has instructions to fix this (section create essential directories):
I also use Rhythmbox, the UI is clean and simple. Other music players either are too complicated (UI has too much clutter, play queues) or want to automatically import all audio files in my home directory into the library, which is annoying. But to be fair, I haven’t tried a lot of other players, because I’m happy using Rhythmbox.
Just submitted, I hope my answers are useful for your research