First, be patient - you can't fix two years of anything without investing some time and effort.
Second, yes, you're going to have to accumulate a lot of volume squatting properly, which will mean reducing weight until you can do that. This doesn't mean you never squat heavy - it means that the vast majority of your squatting volume needs to be correct. For example, squat light-medium every single day. Sets of 3-5 or more with weight that allows perfect reps. Even try pause squats so you can really strengthen that deep position with an upright posture and focus on maintaining it as you recover.
When you work up to heavy weights, keep any heavy reps low, e.g. singles or doubles, and build up a lot of volume as you warm-up - this is more practice and training to fix the squat and will help those heavier sets be better. Then after those heaviest sets, do a few back off sets with a reduced weight and 3-5 reps, again making sure they're done right.