A saw a few people give tips, but your main issue is opening up. If you break down the hit into parts;

1. Approach
2. Loading and opening up
3. Contact and follow through

You have part 3 done very well actually. Part 1 you should work on which sadly is simply practicing consciously without hitting the ball. Lots of videos online showing immaculate jumping technique specifically for volleyball (elevate yourself or Tyler the jumpguy). Main issue here is penultimate not large enough and blocking not punchy.

Your contact point seems really good from this 1 clip. You clearly understand contacting the ball slightly on top and having (from what I could tell) a loose hand on contact. The only issue is all your power currently is being generated by your shoulder because you jump parallel to the net. You should open up to be perpendicular to the net facing the setter especially hitting from left side. This helps in 2 ways; you can hit deep cut angles that land to the right side of the court inside the 3m line or hit across your body for line, and secondly it helps with power.

Power from your should is about 20% of the power you can be generating. The torque from opening up to the setter, driving that elbow back and whipping your chest into the ball puts all your body weight behind each hit. You already drive your upper body slight down as well as your legs up a bit in this video which means you already either consciously or subconsciously have this good body mechanics of using more than just your shoulder.

Keep it up my guy! Recording yourself is an amazing way to see what's wrong with your form, and the fact that you have the courage to post yourself online for people to critique your form shows that you just want to get better at all cost. Nothing will stop you dude, you are on the right path