Yeah look, the method or type of expansion the Slavs did isn't the important part, plus the territory wasn't some Terra Nullius that Polesian Slavs wandered into and then peacefully built cities upon. I got the sparknotes abridged version of the history, but I was mainly using it to make a point.

The point I was making for the OOP who said "God put us Ukrainians where we are to hold back Russian imperialism like XYZ in the Bible and prevent Moscow from bringing darkness to the world" which implies the Abrahamic God directly creates nation states. Then the next logical question would be "well how did Russia get there?" The aforementioned God made Kiev expand to the White Sea in Finland to the north and modern day Russia to the east so one day, as part of its divine plan, the descendants of Kiev would be able to oppose Russia, who are different descendants of the Kievan Rus?

Which specific group of people that was displaced/assimilated isn't the crux of my argument. I don't know the name of the people who are descendants of the Scythians, I was picking away at a delusion of a divine destiny.