While thinking about weaknesses I’ve come to understand that you can categorize a weakness as either muscular or positional. This categorization will determine how you can work on that weak point.
Muscular weaknesses arise when a muscle or group of muscles is proportionally underdeveloped vs. the rest of your musculature. For example, you may have neglected upper back work and therefore it’s difficult for you to keep your chest up during squats. The prescription for this type of weakness is fairly straightforward. Direct hypertrophy work will bring up the weak area quickly. You can also use certain movements which place a focus on the area, for example, front squats for the upper back.
Positional weaknesses are not so straightforward. We’re all weak off the chest in the Bench, the hole in the Squat, and off the floor or at lockout in the deadlift (depending upon your setup). In the Bench, you have to accelerate the bar from a dead stop (at least during a competition). Strength off the chest is going to limit your Bench no matter how hard you work the musculature. Keep increasing the weight and at some point you will be unable to generate enough force to accelerate the bar to lockout. There’s not much you can do to fix this kind of weakness. You can practice the movement in the weak range of motion, pause squats/bench, etc. This will get you more comfortable in the ROM. But increase the weight enough and you’ll still fail.
Targeting a positional weakness is still useful. It will still train the general movement which is never wasted work. It will make you feel more comfortable in the disadvantaged ROM. It is also a great way to make the movement harder which will in turn make the competition movement stronger. It just won’t have as large of an impact as fixing a muscular weakness will.