Sounds like you are suddenly agreeing with me, perhaps inadvertently. The core of that is that empires caused both of those world wars. And we have two nascent empires on the scene in Europe right now. The only way to peace in Europe is the absence of those empires, but no external force is trying to make them go away right now.
World Wars I and II were not caused by the split of Central or Eastern Europe but due to nationalities being across imperial boundaries
Please learn your history. That's carving up Eastern Europe again, and that always led to war.
There will be in fact the opposite of what you stated - since a Western Ukraine would be overwhelmingly "Ukrainian", it would be better for relations between East and West
There is no external force which can make Putin go away. He will self-implode or become a tyrant, but it is only the Russian people who can decide that -- that's not idealist talk, that is a fact.
What external forces can do is build up defences against a future Tsarist Russia.
And the place to build this up is in Eastern and Central Europe.
And the only ways to do this is to use natural boundaries - of which the only ones in the east are rivers, the Niemen and Dnieper rivers as I pointed out above AND to have the realization of Międzymorze -- unity of purpose of the nations from Finland to Western Ukraine.
They've not been able to do this since Jan III Sobieski and right now two things stop that -- the population in Eastern Ukraine and Lukashenko in Belarus.
Cut off the Eastern Ukraine -- it's already lost -- and you have the best two defenses on the south-eastern flank against Russia -- a united Ukraine and the Dnieper river.
Read Zamoyski's book on the 1920 Polish-Soviet war. Piłsudski from 1918 tried to cobble up a union of Lithuanians, Poles and Ruthenians (Belarussians and Ukrainians), but this failed -- to a large extent the Ukrainians by trying to fight for everything, lost everything. in 1920 a Soviet horde advanced westward and the only thing that stood in its path was Poland. But the Poles lost early battles as there was no natural boundaries to halt the Soviets in the lands east of the Pripet marshes.
Only when the Soviets came to the edges of Warsaw were there natural boundaries to hold them off. Piłsudski gambled and brought the Soviets all the way in and then crushed them mercilessly -- so mercilessly that they never dared move westward for another 20 years
you want to stop a Russian advance east, then give up some indefensible territory that is already lost (in the minds and hearts of the people there, in Eastern Ukraine) and build the network from the Neimen to the delta of the Dnieper.
Firstly, eastern europe is from the lands of Lithuania to the Ukraine. Central Europe is Poland-Germany through to Greece.
Secondly, "carving up Eastern Europe" has not caused war -- "carving up European people" has caused war -- people, not land.