I would suggest working on your form more than just letting your knees dive forward so much. It seems as though you are still able to go lower, as far as the arch in your back goes.
Honestly I would dump the heavy back squat for now. If you want to squat and not waste your time do some max work with front squats so you can actually get depth. If you don't like that idea keep the back squat much lighter and keep pushing your mobility and flexibility work.
Also, try keeping your elbows lower. You will be stronger out of the hole.
Lastly, dump the deadlifts for glute activation. They hit the glutes well, but not if you cant activate them. you'll ruin your back before the deadlift helps you activate your glutes by the way youre pulling. you would be better off doing glute activation before/between pulls