You know, you raised something in my mind; The Germans committed the Herero genocide in, what, 1898? Okay, 1904 to 1908. The idea that the Germans needed to look outside for inspiration is preposterous on it’s face, they’d already committed genocide in their own colonies.

The one reason they'd need outside inspiration is that doing a genocide in a colony is a bit different than bringing the empire home. The colonial apparatus is already primed to do violence against the colonized population. The reason they needed inspiration is because a double sized colonization where you colonize the periphery (Westward expansion) and you recolonize the imperial core (Trail of Tears, slavery, population transfers, Jim Crow) at the same time was really an American invention.

The conflict between agriculturalists and pastoralists/nomads is such an incredibly deep conflict in human history. Any suggested reading for how Khazaks experienced the USSR?

Good overview for the Sovietization of Central Asia is

Inside Central Asia by Dilip Hiro

Nomads and Soviet Rule by Alun Thomas is on my reading list but I haven't gotten to it. So I cannot vouch for its quality.

There's not a lot of "friendliness" in portions of this history so you're not gonna get a lot of good feelings but I've heard good things about:

• The Hungry Steppe -- 1930 famine, it's an anti-Stalin polemic so you have to critically read where Cameron is pushing something that she can't actually back up
• Atomic Steppe -- How the bomb was developed in Kazakhstan
• Steppe Dreams -- Post-Soviet studies

In practice a lot of this is really the history of colonial conquest...

Japan's Siberian intervention, 1918-1922. tells the story of Japans attempt at the same region during the same time.

There is also Ostsiedlung and the so-called "Germanisation" of western slavic peoples like Wends, Polabians, etc. going back to like the 9th century; this historical record was used by the Nazis for the justification of Lebensraum.