So can you then stand up from the bottom of the squat? Maybe you just need more aggression at the catch ? Maybe quad weakness? How’s your thoracic, are you quite rounded at the catch? I’d try squats with bands to help build that acceleration through the full movement. Try Defraco’s 50-Rep rythm squats. One set of 50 quarter squats for time at 90-100% with bands with plenty of speed in both the concentric and eccentric. If that doesn’t improve your strength in the top quarter of your squat I don’t know what will! It should definitely improve your ability to decelerate the load at the catch too!