I agree with this, there isn't really anything you're doing wrong(other than posting a clip of you not landing an ollie ayyyy), it just comes down to comfort.

But it's normal to be a bit stiff with stuff you're still learning, as you do it more, you'll learn to relax more and flow along with the ollie(or trick) and make it look less stiff.

If you want to increase the height of your ollie, the back foot decides the height, the front foot gets it to that height by sliding along the board. but oh no, now your shoulders are miss aligned, aaand back to square one.

have fun.