Hey Myles
Set 1 is filmed correctly. 2 and 3 aren't as helpful. Rear 45 for squats initially.
Your issue is your upper back. See how your elbows start to rise as you descend? That's your upper back starting to come out of extension. With the bar wanting roll up as you lean over, you just won't maintain the back angle long enough to keep the ass back and the knees from popping forward.
Don't hang your head off your shoulders. Get your head up, lift your chest and squeeze the scaps together before each rep. Then just lower your eyes on to your target before you descend. Fight to keep the elbows from cranking up as you descend, and you'll have a better shot at keeping the upper back tight.