The way Simo takes air and stablizes his body is almost boner inducing. For squats, this is critical…your whole body has to be ready for it.
The others have spoken to technique, I will speak to the psychology. Either you are controlling the bar, or it is controlling you. In that video, it looks like the bar is squatting you, not the other way around. Go up to it like you own it, get BOTH FEET under the bar during the unrack and lift it off like you are the boss. You should feel such a brace in your entire body that it does not feel heavy at all when you take it off the rack. This is half the battle.