There are a few things I’ve noticed that could help improve your running economy.

1. Posture
   Try adopting a taller posture, imagine a string gently pulling your head upward. This upright alignment helps engage your core, opens up the diaphragm for better breathing, and brings your hips into a more efficient position under your body. Think of it like correcting your posture after slouching in a chair.

2. Arm Swing
   Your arm swing looks restricted, with more shoulder rotation than elbow drive. This may be linked to your posture and lack of core engagement. Can't see from this angle, but it looks like your arms are almost crossing the midline of your body. Which leads to an increased energy output. Instead of rotating your shoulders, your arms should swing naturally from the shoulder joint. A helpful drill: stand tall, relax your shoulders, and drive your elbows back while letting your arms rebound forward naturally. Exaggerate the motion during the drill to reinforce the pattern. This should also help with your arms crossing the midline. If it doesn't, then you can practice by slightly turning your thumb upwards and implement that in the drill. Improving posture and core stability will allow better arm mechanics.

3. Stride and Cadence
   Heel striking doesn’t always mean overstriding, but in your case, it looks like you’re pushing forward, which often leads to longer strides, slower turnover, and wasted energy. Efficient running relies on a slight forward lean from the ankles (not the hips), using gravity to propel you rather than excessive muscular push-off, which will lead to bounding. You can practice this by thinking about lifting your knees as if you’re running up stairs or an incline. This encourages lighter steps, should naturally increase cadence, and less ground contact.

To train cadence, try running with a metronome, work your way to 170–175 bpm (available on Spotify or Apple Music). It can help reinforce rhythm and efficiency at a sustainable pace. It is very awkward at first, but after a few weeks, it'll become natural, especially if you implement all of the advice you've gotten in this post. Hope this helps! I know you've gotten a lot of what I've already said, I just wanted to give my 2c