Not so fast! If you are a conventional DLer box squatting won’t help your dl a great deal unless you have some serious overall weaknesses or are a newbie. But if you are a sumo puller low box squats will help your pull off the floor like nothing else.
If you are a conventional puller, doing dls while standing on 45lb plates or 1-2 inch platform of some sort is option 1. Keep reps at 3-5. 2-3 sets either as assistance or as the main dl workout most of the time.
Then you can do pulling squats, which are basicly high bar squats with a dl stance done very deep to a pause.
i would also check leg imbalances. Try doing some bulgarian squats and make sure oth legs are equal in strangth and stability.
last thing is to do some ab work with feet on the floor. Pushing or pulling vehicles or sleds, standing cable abs, med ball throws.
One last thing, when my squat goes up, so does my meet dl, although as my squat workouts get better my dl workouts peter out a bit from fatigue.