They might have the upper hand over NATO if the USA did not take part in a confrontation or outright war.
In the 1950's I was a member of a SAC Think Tank which was planning for WW3 versus Russia.
When Stain died, we & the rest of the intelligence community breathed a sigh of relief.
It was thought by many knowledgeable people in the intelligence community that Stalin was neurotic or worse. Communists had a belief that it would eventually take over the world.
There was a fear that Stalin would start WW3, desiring to be the Communist leader in charge when communism triumphed.
When he died, it was known to both sides that WW3 with nuclear weapons would destroy most (if not all) of the major cities in each country.
United States has hundreds of (perhaps over a thousand) small to medium towns with libraries, engineers, small manufacturing facilities with machine tools, technicians, medical facilities, automobiles, trucks, & other modern resources.
Almost all such Russian facilities & human resources are in major cities.
It is possible to drive from coast to coast in the USA using secondary roads.
Almost all Russian roads go through major cities.
The USA would be modern culture recovering from a disastrous war.
Russia would be similar to a 12th to 15th culture, with few engineers, technicians, libraries, manufacturing facilities, et cetera. While some automobiles & trucks might still be usable, they would be seriously limited in where they could go.
The Russian leadership of the 1950's were aware of the above. That is why Kennedy could demand that Russia not put missiles & other weapons in Cuba. They knew the USA could invade Cuba or destroy such weapons/facilities by bombing them, without fear of Russian retaliation.