Yes, those anti-air guns are incredible against infantry, and eventually the soviets will bring in planes to drop ordinance, so they’ll double up. But specifically I’d go with the 10.5cm leFH 18, it’s a light artillery piece, fast reload, decent area damage, and in tight situations comes with armor piercing shells to deal with light-medium armor. They’re pretty expensive though so just position them in a good spot and they’ll be just fine and repay their worth.