I am going to butcher this explanation, so fair warning
I think you could start thrusting forward with your glutes earlier in the lockout portion of the lift (once the bar is about knee level). You finish violently with your knees, but not really with your hips, and getting your glutes engaged earlier and with more force will help locking out your 1RM attempts. Maybe locking your knees earlier in the lift might help too, but I am not sure how common or uncommon your way of doing it is.
Hopefully someone with better fundamental understanding can chime in, but the core of my comment was that your hip lockout looks a bit "soft".