The majority of the fighting was conventional (either European linear field warfare, or European-style sieges like Boston and Yorktown) and the British would not have been defeated were it not for the large, conventional Continental Army fighting in lines wearing uniforms in open fields (even though they didn’t have success in most of the individual battles.)
The militia was mostly useless (as was also true in 1812), despite attempts to glorify them by those violently opposed to a standing, real army. They were of use in certain isolated circumstances when properly used, like Cowpens, and the militia vs. Loyalist militia battle of Kings Mountain.
The most effective irregular warfare ambush of the war was a Loyalist/Indian ambush of American militia at Oriskany.
The “myth” though is embodied in the Bill Cosby routine about smart Americans shooting from behind rocks and trees against the stupid British in bright uniforms standing in neat lines.
Actually the Militia in the South caused the British to divide their forces and waste resources dealing with them. The Militia played a much larger part than you are giving them credit for.
France naval power decided the conventional war; the British could have held the coast indefinitely were it not for their interference. The smart colonists shooting from behind rocks and trees made places with rocks and trees ungovernable to the British