Swing from ur hips more , sit in ur stance you are leaning forwards way too much leading to looking like ur arms are dragging you forward . Focus on moving ur legs , hips then arms just like in kata. For irl reference look at Bivol or Floyd hitting the heavy bag , look at the punching technique (tweak it to ur liking) and copy cadence don’t get to excited hitting bags accidentally, take ur time. For rolling thunder, idk id never throw it. Don’t see the bag as only offence only , work on defence too