Your single game looks a lot like mine, you have similar issues like me, so I can feel with you I believe, that getting the split step into your game routine is one of the hardest things to learn, once you fall out of continuous training sessions Eg. at 2:24, a split step should have helped you there. I've the same issues and I try to integrate the split steps in every single training unit I do. Back to your footwork to the backcourt. I think, that your footwork starts really nicely when going back. You do the right steps, you are fast enough to cover it most of the time. But once you hit the shuttle, your routine falters. E.g. at 3:05 and 3:08 your racket leg moves to the side. It looks somewhat weird, in your training sessions it looks a lot more naturally. E.g. at 3:21, 3:27, 3:52 your follow through is missing. Even if you are just doing a drop shot, try to keep up a follow through. The basic clear, smash and drop should follow almost the same movement pattern with adusted hitting angle and power. If you get this right, you have a really strong foundation for three really important shots in badminton. I would sugguest, that you, as you seems to already do it, concentrate your training on a single routine and do it over and over again (include the split step). Take a look at 2:07, there your double routine kicks in, take a step forward to cover the front court. Eventually this will happen to your split step, scissor kick, follow through etc. too, just keep it up .