Compared the the first video, your lower leg seemed a lot sturdier and you have better rhythm. Your reins got shorter with the 2nd video which due to your upper body being stiff and not loosey goosey the horse was a little confused by your "go ahead and move forward" cues because you didn't have much release in your elbow and your hands would go up as you posted.
At the end, like a second before it ends, the horse relaxes because you dropped your hands and relaxed for a split second.. then when he head went down I'm not sure if you felt she (or he) was going to yank you down but you abruptly lifted your hands up a good inch and the horse went back to bracing.
I agree with tinyliny, just more riding :) I'd focus more on relaxing and maybe some 2-point work to get that lower leg even more sturdier and make you less reliant on those stirrups (though it wasn't bad.)
Also work with longer reins until your horse begins to relax and then slowly as you ask for more forward, you can take up a little of the rein and push the horse into the contact (instead of hanging or pulling on the reins.)
It was a great improvement :) Just focus on relaxing. I'm working on it too.
"Strength is the ability to use a muscle without tension"