confidence issue - you start trying to hit fadeaway shot let go of your a and d when shooting(try it for some weeks and then start in range with a only and d only movement)
most definitely mouse control
shaky aim usually a sign of too much tension while aiming
try aim training with a focus on precision, smoothness, and tracking tasks while also making sure you manage your arm and wrist tension properly
then start aim training bro
no reason not to if you have time
10-15 mins per day of good practice with proper technique and your aim will get less shaky for sure
Most common reason is people death grip their mice. Try some dms (or aim training pref) while being conscious of this. Should help you alot, tension management is an important skill to learn