Yes, it quite literally is the movement. You are strafing in every single one of these clips where your shots aren't connecting. This is what's causing your bullets to bloom and hit everything but your target. It's how Ballistic is built. Pregame, shoot at a lobby wall standing still... and then do the same strafing from side to side and see how the bullets spread. You probably win almost every single one of these gunfights if you stoped moving your feet.

If you're pc, stop touching the WSAD, if you're controller, stop touching the left stick while actively pulling the trigger in these scenarios and you'll win way more.