I went Benedict Arnold and drove a Churchill Mk VII for a bit. It has the Sherman's great HE, sucky AP mid-velocity 75mm gun on a chassis that waddles forward and backward constantly from shit suspension and manages ten miles an hour on a good day. But man, did I go to town. Took out an AT gun, a StuG, and a Panzer IV by simply keeping my front armor to them while waddling my stupid, fat self on by, slamming out rounds with no particular reason. The Panzer IV got my turret crew knocked out, though. I broke onto an Axis airfield and proceeded across it, only to be jumped by another AT gun and a Panzer III H that was sorely outclassed against my armor. What do I do? Back into a hangar, use the bow MG to shoot planes taking off, and ignore the incoming point-blank fire for some five minutes until a Panzer IV flanked me through the back of the hangar. What a hillarious time.
Yeah, allies are easy mode and Axis is getting stomped this campaign. As an infantryman stick to the bushes and the berms, stay low, sprint in little bursts and dive behind cover, constantly watch for the enemy and be cautious, observant, and smart. And never underestimate the superior effectiveness of your rifle against exposed infantry with the range dialed in. Leading isn't much of a concern against a jogging infantryman, just put the sights about one yard ahead of him for every hundred if he's running due left or right, half that at an angle or if jogging, or just put the sights on him directly and shoot under 100. The bullet is very, very fast, and in a normal engagement leading isn't much of a concern at all.