I'll take only minor issue with this. If you group Galicia, Volhynia, Transcarpathia, Zapporizian Cossaks, Don Cossaks and the Crimean Hetmanate under the same "Borderlands" nationality (first in existence in 1922) and culture, we can quibble. Ukraine as Kievan Rus existed long before Russia.
With this I can quibble more. Kiev as a trading city was burnt to the ground and its entire population, men, women and children, were slaughtered by the mid 13th century Mongol Invasions. No city within the present confines of the borders of modern Ukraine were spared. East of the Dneiper became the Wild Fields because of slave raiding, etc. So there really isn't enough continuity to put meat on the "Ukraine as Kevian Rus" phrase as you employed it.
I think that’s exaggerated a bit. Be that as it may there was certainly cultural continuity even if there wasn’t genetic (Which I doubt was zero!).