I think that after cessation of hostilities in Ukraine there will happen a significant additional, bidirectional, resettlement analogous to displacements you’ve described. Ukrainian diaspora will only enlarge, till it surpasses the population of Ukraine proper by wide margin, as it happened with Armenians. (Who, after all, speaks today of the exodus of Artsakh Armenians?) You will become the biggest divided folk in Eurasia, or maybe the second biggest after Russians.

The war has all potential to become yet another permanent conflict, akin to Israeli-Palestinian “relations”. From the Dnieper to the Azov Sea, Ukraine will be free, eh?

There are folks on South-Eastern territories of Ukraine, already annexed by Russia, who honestly can't stand bigotic, corrupt, and anemic Russian government; there are also people in Ukraine who would vehemently oppose Zelensky and his cronies, had they some kind of protection of civil rights against oppressive apparatus of ultraforced nation-building (embolden in slogans like І на деревах замість листя висітимуть сепаратисти). Members of both groups shall be given chance to change places of interest and residence.

All that said, Ukraine as a self-sufficient state is, alas, probably finished. Atrocious war losses are simply the logical finale of multidecade irrecuperable process of erosion and breakdown. However, евроинтеграция явочным порядком has been, indeed, accomplished, though highly likely many proponents of 2004 and 2014 revolutions would like to reassess the votes they cast. The price is clearly too high.