> It would only work if the elephants were completely disciplined and ignored injury, death of friends, and noise

How about drugged elephants then? What if, in this increasingly sci-fi alt history setting, the elephants were just smart enough to figure out a) what kind of plant, mushroom or whatever makes them go berserk, b) realize berserk elephants are much better at effectively fighting humans, c) were willing to make individuals sacrifice themselves for the herd, and d) were able to consistently use berserk assaults as a battle tactic?

I know it's a lot of assumptions, but I won't have mere historical facts make me let go of the image of OG ultralisks attacking pre-industrial humanity.