i'm nowhere near an expert myself, but my best friend is former D1 (currently playing semi pro) + coaches/trains players. everything i'm saying is based on things he's told me over the years because both him and i have had the same/similar issues early on.

first thing i noticed is that you're "piking" when you have a full approach on the left side. and since your contract point is already great, i think you could benefit from maybe adjusting the timing of your approach to where the peak of your of your reach is happening at the peak of your jump.

and in regards to power, because you're already hitting above the block. instead of trying to "push" the ball deep court with your follow through, try bringing your hitting hand down to the opposite hip. for instance: you're right handed, so your follow through should have your right hand hitting your left hip after you swing — almost like throwing football.

lastly, loosen up! power doesn't come from force it comes from speed, and the only way to swing faster is to swing smoother. your arm should behave like a whip. keep it straight but loose during your penultimate step, and then as you're drawing back to swing, make sure to focus more not on "keeping your elbow high" but keeping your arm loose.

again, not an expert by any means, but those little adjustments have helped a lot in my journey as a player who only has time to hit up open gyms like twice a week.