It is false.

The Soviet Union never had any control over Finland.

Russia never had complete control over the Caspian Sea or the Black Sea.

After WWII, Poland was formally an independent country but militarily and economically associated with the Soviet Union. I lived there. In my articles, you can find that influence stifled the Polish economy but was not absolute. We used the little freedom we had to fight back, and we won. The Soviet Union was due to disintegrate, but the Poles triggered the moment.