I suffered a partially herniated disk doing squats, and no longer do them. Sooner or later, you will go heavy enough so that you may screw up your form trying to get up, and bending forward but a few degrees can cause a herniated disk.
Also, Kovacs doesnt squat in his video. He does leg presses with what looks like 15-20 plates per side, and uses good form.
Problem with leg presses is that many people put on a lot of weight, then go partially down and think they are strongmen for having so many plates per side. Try going down as far as you can and back up and leg presses will be effective.
I do smith machine squats, leg presses, hacks...but these days smith machine squats. The Smith machine is great for partial reps,. ie at the bottom of the movement, squat all the way down then back up but only to parallel, then back all the way down. Now those hurt!