Thanks for posting the match video. Much better for analyzing than hitting agains t a wall. You are absolutely correct on movement and court positioning. A couple of very simple suggestions: (I will leave the more techinical stuff to the coaches). There is nothing even remotely resembling a split step or even being "on your toes". You are completely flat footed, standing and waiting for the ball to come to you before moving. Easy concept to change. Second simple thing. When you serve in the deuce court you are standing way too far to the right or near the sideline. That would be about the place to stand if you were playing doubles. Standing there, you have too much ground to cover to the left.
Good luck with your tennis progress.