I think Scotts are one of USA's most important units when used well. However you have to remember they are useless upfront in a fight.
When facing this as Werh, I spammed P4s keeping them back, when I had 3 with MGs and some added vet from Elite troops, I charged the ATGs from multiple directions and used smoke on whichever P4 took a beating to keep it alive.
Its not easy for the ATGs to stand up to, and the American lacks propper armour to reppel the push, or strong AT infantry (like Rangers), then the scotts will be easy pickings.
AT vehicles like Panthers or JP4 cant do this because they lack the AI to kill the ATGs in time and they are fewer in number to medium tank spam, so easier for the ATGs to target.
Obviously infantry or support weapons cant get close thanks to the Scotts.
So as OKW, this tactic would only be acheivable with P4 call in (probably unrealistic?), perhaps Luchs spam? Dunno how that would go
Or you could go 2x Stuka, given he has nothing to chase them down with, only static AT. Attempt to vaporize the ATGs and grab a puma to hunt scotts?
So basically, light mobile armour, try to counter the ATGs without taking too many losses. Thats the Americans weakness, the way I see it.