If the Nazis had free labor, they would have done better, but they still would have lost because the US was bigger.
The USSR likely would not have prevailed against the Nazis if the US didn't supply them. Or at least it would have been far more difficult for them.
Synthetic rubber - "Production of synthetic rubber in the United States expanded greatly during World War II since the Axis powers controlled nearly all the world's limited supplies of natural rubber by mid-1942"
Synthetic fuel - "During World War II (1939-1945), Germany used synthetic-oil manufacturing (German: Kohleverflüssigung) to produce substitute (Ersatz) oil products by using the Bergius process (from coal), the Fischer–Tropsch process (water gas), and other methods (Zeitz used the TTH and MTH processes)."
The USSR likely would not have prevailed against the Nazis if the US didn't supply them. Or at least it would have been far more difficult for them.
Synthetic rubber - "Production of synthetic rubber in the United States expanded greatly during World War II since the Axis powers controlled nearly all the world's limited supplies of natural rubber by mid-1942"
https://en.wikipedia.org/wiki/Synthetic_rubber#World_War_II
Synthetic fuel - "During World War II (1939-1945), Germany used synthetic-oil manufacturing (German: Kohleverflüssigung) to produce substitute (Ersatz) oil products by using the Bergius process (from coal), the Fischer–Tropsch process (water gas), and other methods (Zeitz used the TTH and MTH processes)."
https://en.wikipedia.org/wiki/Synthetic_fuel#History
The V2's were fueled by alcohol from potatoes.