The USSR acted as a serious meat grinder, but a little less than half of German losses where on the eastern front which also included polish forces and the USSR had minimal impact on the Pacific front.
The US footed a lot of the material costs needed for Europe and the USSR to stay in the fight via lend lease. To the tune of about $575 billion inflation adjusted, and 22% of that going directly to the USSR. https://en.wikipedia.org/wiki/Lend-Lease
So, the USSR played a significant role, but where far less effective than your suggesting.
The US footed a lot of the material costs needed for Europe and the USSR to stay in the fight via lend lease. To the tune of about $575 billion inflation adjusted, and 22% of that going directly to the USSR. https://en.wikipedia.org/wiki/Lend-Lease
So, the USSR played a significant role, but where far less effective than your suggesting.