Reading this makes me realize Russia is the true multicultural nation.
Indeed, you are right! Even from very ancient times. Even the Russkies themselves I think came from different tribes or different peoples, as they included them into their empire and/or civilization, which existed before Christ even. Do doubt it was different back then, but Russia still existed as a civilization in one way or another. It's very similar to China for example. Unfortunately real true history was demolished by Peter "the Great"'s pseudohistorians and Western academia at large. China kept their ancient history intact for the most part, although internal spirit, true patriotism, and societal cohesion no doubt played a large part in this, the other reason is that the assault on China was only 100 years in duration, compared to on and off more than 100 years for Russia.
Anatoly Klyosov says that Russkies have three main haplogroups: Aryan, Uralic, and Balkan. These tribes, or groups of tribes coalesced to form the Russkiy people. There is a lot of residue implying that the "Russian civilization" or "Eurasian civilization" directly or indirectly extended outside the bounds of the 19th century Russian Empire, culturally influencing even more distant lands.
How can we say that the Russkies are made up of different tribes? There are at least five distinct words in the Russian language that mean "horse", that I know of. There maybe more such words that I haven't encountered yet. But this all is very telling, that there are multiple words for "horse". Is that the Russkies were once steppe nomads and/or were brother nations with other steppe nomads, who all lived in the same empire. Different tribes came together, either voluntarily or by political coersion, and they all used the words that were familiar for them. I do not know Mongolian, Uighur, or Sikh languages, but I suspect that that we might find some interesting words in those langauges as well.