The USSR would span its territories in the 80s but be led by a competent Marxist leninist party. Same for the Warsaw pact countries and Yugoslavia. These were caused by revolutions popping up all across the globe and other areas.
The US choice would have itself devolve into chaos while its power and influence decreases. Infighting would break the US into pieces but territories like hawaii and alaska would gain independence. The main government would be torn asunder and the CIA rogue and unfunded.
Honestly second choice is already happening so neither of these choices really matter if we don’t have the second option be a more reasonable thing like “The US empire dissolves without the chaos that will start off nuclear Armageddon.” Revival of the USSR would only exacerbate the issue and at best give them a new enemy to throw their focus onto to stave off the collapse for a bit longer. At worse they are just a new reason for more nukes. So reality is this post is really just “what if the USSR was back?” Which would be pretty great for sure But it doesn’t solve the issue that the US will probably end the world eventually. At least that’s how I see it.