Def looks like controlling over-rotation is the issue. Do you have access to the snowboardaddiction.com vids? Sure there'd be something on those. I remember the back 1s trick is to look back up the landing so you don't over rotate into a 3.
Looks like your head and upper body is stationary in relation to your lower body through the rotation. Can you counter-rotate just before landing to help slow the spin?
That jump has lots of crazy angles going on, and being corked don't help lol! The angle your board and body would have to be on may be a little odd to stomp it?
Good fun to watch
Along with wanting to naturally cork spins, do you also prefer angled/side hits to straight kickers?