The first rep was a mess, not even sure how to explain it, but then your form gets better on following reps. i paused it at one point, and your legs were straight, and your upper body was exactly paralle to the floor, like your about to do a BB row. try pausing the second vid, right when your legs are straight, and see I had a similsr problem of straightening my legs first, I had a coach fix this by having me deadlift off a box, seated believe it or not, hard to explain on line.
I think you should try some touch and go reps, ''starting from the top'', staying real tight, and being aware of your form, just as you touch the floor. I'v seen this work real well, becuse most people lower the weight with better form than they lift, just a sugestion, you'll probably get alot more as well. Some heavy pin squats, 3/4 depth, from right where your hips are during deads, seen this work as well. I don't know, takes alot of guts to put your shit out there to be judged, thats how ya get there. I'm sure some strong guys will weigh in. Goodluck