You and your horse are both troopers!!
I lost all of my confidence as well, a couple of years ago. And in the same situation; the pony I was riding at the time refused, refused, refused jumps. I ended up going back to a steadier horse for a while, then returning to the pony I lost my confidence on. That helped a LOT. Proof is, I have my confidence completely back.
What I got from the video was that is looks like you let your horse get a bit flat and strung out in the canter, in between jumps. Then when he tries to run out, you no longer have the control or balance to keep him straight.
I would work on lots of trot/canter transitions, gymnastic work (one or two strides in between jumps), bounces, poles, and more more more transitions :) Rounding him out more and keeping him in check will be a huge advantage when you're trying to prevent a run-out.
Also, my coach NEVER tolerates run-outs... if a horse ever tries it, she has us stop the horse (like, slam on the brakes) within the stride and back him up, THEN re-approach the jump. I've actually found this to be a great training aid. You could maybe try it.
I, for one, would suggest that instead of going into two-point, you stay deep in your tack to the jump. If you are in two-point and your horse runs out suddenly, you're not in the most secure position to recover. Your most effective position is sitting deep in the saddle, eyes up and leg on.
I agree that your release could be more generous, and going back to smaller jumps might help
Kudos to you and your horse for trying :)