I'm curious what the factors were that led to the modern post-Soviet borders.
Why the -Stans fell into the shape they are now: why Kyrgyzstan, Uzbekistan, and Tajikistan share that strangely shaped entangled border.
Why other ethnically non-Russians did not try to form their own states, such as native Siberians in eastern Russia, or turkic and north georgian peoples of Dagestan?
Why did Belarus become a separate state when they are so cultural similar to Russia?
Why didn't Moldova join Ukraine or Romania? Why did a poor landlocked subsection become independent?
Why did Kaliningrad stay with Russia?
Why did Ukraine take with it a large chunk of territory whose people self-identify as Russian?
Lastly a curiosity question: did China or North Korea ever try to lay claim to a piece of Russian land when the Soviet Union disintegrated?
Each one of those questions would require a good deal of explanation on their own. Although they are all very interesting and I would like to see someone who knows their stuff answer them, I doubt thats going to happen.
At least in terms of Siberians, there were very few of them, and due to both the importance of Siberia to Russia, in terms of resources and security, and the fact that there are barely enough people there to start a sovereign nation, I don't think anyone anyone was trying to get them to be independent.
Also, there has been a lot of currently ongoing conflict relating to muslim and georgian people in Dagestan wanting to be independent, so theres that
Ok, so lots of questions and each of those require a pretty detailed explanation, so I'm going to go for some low hanging fruits:
Why the -Stans fell into the shape they are now: why Kyrgyzstan, Uzbekistan, and Tajikistan share that strangely shaped entangled border.
Because Stalin set the borders that way on ethnic lines during his time as the Commissar of nationalities. He redrew a bunch of borders which previously defined the region under Soviet administration and created Soviet Socialist Republics for certainly ethnicities as administrative divisions. Their mostly nominally federal status meant that they subsequently gained independence during the collapse of the Soviet Union.
Why did Kaliningrad stay with Russia?
It has a majority ethnic Russian population and was legally a part of the Russian Soviet Federative Socialist Republic. Therefore, when the union fell apart, Russia still owned the city.