The biggest Soviet problems with their armor in the early days of the war was not quantity or quality. It was support.
They had almost no provision made for refueling, reprovision or ammo supply. Maintenance did not exist.
So a tank group would go into battle, and promptly run out of gas and/or ammo or break down.
Hard to imagine anything more vulnerable than an out of gas tank.
The absence of such support was probably at least partially related to Stalin’s destruction of the officer corps. And something that should be remembered when US combat troops complained about the support troops not fighting.
I don't know how much armor the U.S. supplied to the soviets, but I've heard we did supply them with a huge number of trucks which were absolutely vital (as you just pointed out). This alone took a tremendous burden off of their manufacturing, allowing them to focus on building more tanks.