I had the same exact problem and I found the solution. GO TO SETTINGS> THEN CLICK ON LOCK SCREEN > THEN CLICK ON FACE WIDGETS AND THEN CLICK OFF ON THE MUSIC SELECTION. That should have taken care of the issue.
Life saver! I have a Samsung S10e and had tried all of the other options! Although I could see the controls on the lock screen, I couldn't actually use any functions. I did what you suggested and boom! All good now. Many thanks.