Literally the reason the USSR had a strong government over the Republics was to keep states like Georgia and Ukraine from becoming ethnonational fiefdoms, while sabotage and insurgency by the CIA stoked Nazism in Ukraine and all sorts of racial animosity in the Balkans, and we have seen the “fruit” of both efforts. The idea that the USSR was Russian supremacist is unhinged. Was there Russian chauvinism? Sure, but that is not the same thing.