Cold War: Realpolitik or Idealogical?

Did the Soviet Union (Communist Party, Stalin, or however you define it) ever really believe they were going to “free the world” from capitalism?

Or did they just get tired of being invaded so they set up a buffer zone in Eastern Europe? And tried to set up other buffer zones other places. As in, well the US and Nato can’t invade us if their busy in SE Asia, Central America, and so on.

Conversely, did the US/Nato really care that Eastern Europe was “oppressed” by the Soviets/Communism. Lots of people are oppressed. Let them have their sphere of influence.

I’m wondering if, in the post Cold War world, any documents came out that either side was actively planning/waiting for an opportunity to strike. I am sure both sides had contingency plans if the other side attacked first.

Likely both, and more, as revealed in documentaries like Pilger’s The Truth Game: