First of all, thank you very much for providing your playercard.
the quickest and easiest way to improve is playing 10 games with wehrmacht while copying exactly the strat you have problems with. you will see immediately how players react to it whcih will give you plenty of insight.
the crucial thing with US is about timing. don't just rush in with your rifles because you think "i have semi autos, so i have to get in close". Use cover and mid range engagements. try to pick up loney grens and attack them from 2 sides with all your rifles firing. Ignore MG house campers and get to their Cutoff.
faster, snipes infantry and tanks alike, has more sight, better rotation, easy crush, a gas shot which oneshots At guns, a normal shot which oneshots at guns, blitzkrieg already at vet0 and can't be penetrated by at guns