It was quite different. The Soviets e.g. released millions of people from Gulags. Nazis did not release people from their death camps. They were death camps. You were supposed to die there.

Some people may like to trivialize the difference, but that is quite a substantial differnece. Gulags were primarily harsh prisons, not something designed as extermination camps.

There is a difference between a brutal rule trying to get rid of opponents and rule which has an ideology that people with certain genetic characteristics or bloodlines must be completely erradicated from the planet.

Soviet oppression was in many ways oppression as we have seen it for centuries just amplified and increased in scale. Fascism/Nazism was a really new thing. Historically rulers had no had obsessions with carefully selecting people of a particular blood line and killing them at industrial scale. This was a novelty in the human history of oppression and barbarism.