Thanks for posting, that's a nice stroke...I like how well balanced you are coming off the wall and you hold that balance well through your stroke.
Some suggestions and observations:
Try to start each length with at least 2-3 strokes prior to breathing, or at least a single stroke. Those first few strokes off the balanced superman glide position are extremely valuable for practicing whatever your focus is without getting disrupted by a breath.
Observe the up and down movement of the back of your shoulder blades through the stroke cycle...not the rotational component...but just bobbing up and down in the water.
My suspicion is that your stroke starts with a palm facing down towards the bottom and slips rearward. This creates a force that pushes your body up in the water, cheating you of the energy that could be used to move forward. I'm not certain without an underwater view.
But I think that modifying the position and shape of your hand and arm underwater will remove this up and down motion and convert it to forward motion...with no additional effort.
Finally...as you continue to improve, work on moving your mail slot entry incrementally forward while still keeping being able to hit your spearing target. Right now, it's a "textbook" TI mailslot entry near the google line or forehead...nudge it forward just a hair and see how that feels.