The only caveat is that the Soviets essentially tried to manufacture ethnostates by forcibly displacing ethnic groups from one region to another, but yes, Russia is ethnically heterogeneous although there is still a good deal of Slavic supremacism present in Russian politics (e.g. conscription disproportionately affects ethnic minorities because they're generally poorer and unable to avoid it or desperate enough to volunteer).
This is also true for China, which engages in Han supremacism (as part of the "one China" policy dating back to Mao), and India, which engages in Hindu supremacism.
Arguably Germany also suppresses some of its indigenous ethnicities, although not as blatantly as during the exterminationist policies of the Third Reich. While there are public institutions to preserve the language and culture of the Sorbian, Danish and Frisian minorities for example, Germany unlike e.g. the US has a single official language and merely "recognizes" theirs (i.e. acknowledges their existence but does not require them to be accomodated in areas where they are widely used).
There are so many things that I think are wrong here.
"Soviets essentially tried to manufacture ethnostates by forcibly displacing ethnic groups from one region to another"
Not really. During the policy of so called "korenizatsiia"[0] (indigenization) Russians were deprived of leadership roles and forced to learn local languages. In the next period Stalin was punishing certain ethnicities for relatively high level of collaboration with Nazis by relocating them to inhospitable regions.
"Russia is ethnically heterogeneous "
I didn't mean Russian citizens, I meant ethnic Russians which themselves are a mixture of god knows what (I'm Russian myself).
"there is still a good deal of Slavic supremacism present in Russian politics (e.g. conscription disproportionately affects ethnic minorities... )"
Many ethnic minorities have better demographics -- they have many more children than ethnic Russians and correspondingly more men of the conscription age.
"This is also true for China, which engages in Han supremacism"
For example, the CCP's draconian 'one family -- one child' policy applied only to Han. [1] Doesn't look like Han supremacism to me.
"Germany unlike e.g. the US has a single official language"
Again, not really:
"there is no official language at the federal level <...> Three states and four U.S. territories have recognized local or indigenous languages in addition to English."[2] Three states isn't much for a whole continent inhabited by Native Americans. Or try finding any Native American language or even Spanish on the web site of the US Congress, for example.
This is also true for China, which engages in Han supremacism (as part of the "one China" policy dating back to Mao), and India, which engages in Hindu supremacism.
Arguably Germany also suppresses some of its indigenous ethnicities, although not as blatantly as during the exterminationist policies of the Third Reich. While there are public institutions to preserve the language and culture of the Sorbian, Danish and Frisian minorities for example, Germany unlike e.g. the US has a single official language and merely "recognizes" theirs (i.e. acknowledges their existence but does not require them to be accomodated in areas where they are widely used).