The Roku TV app shares similar functionality with other TV apps, and currently it's not possible to sort and arrange your music in the same way the regular app does. There's always the option to use the Connect feature with your TV instead, so you can use one of your other devices to control the music on the TV. Find more info here.
If you think this is a good idea, feel free to leave it in the Ideas Exchange. You can find it here. There is a few ideas about improving Roku but we couldn't find an idea that was about the ability to sort playlists on Roku.
Hope we'll see your idea(s) there soon. If you have any questions for us, please let us know.