“Putin doesn’t want to bring back the Soviet Union.”
You sure about that? Because he brought back the national anthem of the USSR, the Red Star is still on Soviet aircraft, the hammer and sicle is on their uniforms, and they fly the Soviet flag everywhere.
The melody of their modern national anthem is the same but the lyrics are completely different.
Red is a color of the Russian Federation.
Putin is a nationalist and wants to bring back the Russian Federation back to its pre-Bolshevik glory. He has zero desire to reclaim Latvia, Estonia, Lithuania, Kazakhstan, and Armenia because he has said that control over those republics spread them too thin. Plus he has indicated on numerous occasions that revitalizing the USSR is not practical. He attacked Ukraine because the Ukrainians were committing genocide of ethnic Russians and the US/NATO were putting forward deployed missiles on their doorstep.