The helmet models on troops is currently the OpsCore bump helmet, not the ballistic version - this is seen by the ventilation holes on top of the helmet, as opposed to the ballistic versions closed design.
In real life the bump helmet does not provide any ballistic protection - which for line infantry is an absolute must, as it's a carbon-fiber/plastic mix designed to protect the wearers head from... bumps and knocks rather than shrapnel and pistol rounds (and on a really good day also rifle-rounds).

I understand there are more pressing issues for the time being, but this is something that should be remedied as the game nears completion.