Two lend lease items from America were Force Multipliers.
The big Studebaker trucks made the Red Army mobile. Especially compared to the Germans in the Winter. All year the German logistics systems were heavily dependent on draft animals for supplies. Horses and other draft animals were severely limited in Winter by being unable to graze. Trucks made the Russians more mobile in the Winter than the Germans could possibly be.
Battlefield communication. America provided a military radio communications networks. The ability to coordinate and deploy Red Army units with each other made them more far more powerful than they were at the beginning of the war.