ok, watching the walkthrough, on half speed to confirm something that i thought might be the case, it SEEMS that for you and possibly on other hardware shots are banking, ie, that they are curving in flight, based on movement of the player, whereas i think a lot of people are firing on the mechanical understanding that as soon as they leave the gun, they fly straight, so they aren't keeping perspective oriented on the target through the flight of the projectile, leading to a lot more misses, than if they camera strafed the target until the shot got there, leading to a hit.
that's not so much a jank issue as maybe just a differing FPS mechanical assumption question, if people are expecting to lead their shots for where enemies will be based on how long the shot will take to get there, and not keeping reticle on target after firing. and if they move off target, assuming the shot will proceed where they shot, and it doesn't, it results in a lot more misses.
see also ho, when moving, and then trying to move the mouse in a direction contrary to the arrows/WASD movement (left when moving right, vice versa), the camera loses sensitivity/movement is canceled out to a degree, making it harder to get pinpoint precision on target, as sensitivity when stationary, and moving, keeps throwing the player off
for context, had to turn mouse sensitivity all the way up to be workable, and even then it was still somewhat limited, but that results in stationary mouse movement being too strong by comparison, and losing perspective/continuous eyes on target