All art in the Soviet Union was state-manipulated propaganda. At least all of it that was in public venues such as theatre and television.
You do not know what you are talking about.
Soviet Union was one of last countries with true art. Art requires seriousness. Western art has turned into entertainment long ago. All movies are made so that you can accompany them with popcorn.
There were topis with sort of a prescribed understanding, mostly related to early history of the Soviets. There were opportunistic authors who produced politically correct slop. These fellas quickly changed course in 90s and now have mostly left for Israel. But there was also massive live stream of true art alongside all that, realistic, serious and even Christian: Russian classical culture is so deeply Christian that you pick it even in an atheistic setting.
That is true to an extent, but Soviet films are not all the same. Great artists like Bondarchuk were able to still tell compelling stories despite the political constraints of his time. Even Seventeen Moments of Spring, which was commissioned to influence the Soviet public to have a more positive view of the KGB, managed to tell a meaningful and very human story. Tarkovsky’s Sci-Fi films are also great and can hardly be said to be state propaganda even if they were considered acceptable enough to be made public. Many Soviet films are heavy handed and wooden propaganda movies (like the ones by Ozerov), but not all.