Iraq, Afghanistan, etc. have not worked out well whether the people in charge were Republicans or Democrats. These places are mixtures of tribal, ethnic, and religious groups that were cobbled together by European colonialists who believed in the principal of “divide and rule.” Fortunatly, except for the Donbas area, Ukraine does not have that problem and seems rather universally united against Putin’s war. I suspect the outcome will be different for that reason. Many people in eastern Ukraine who were ambivalent before have declared solidly on the side of “Putin go home.” And they have been putting their lives on the line therefore.
I’m not an expert on Ukraine but I do know it has been part of many different kingdoms and nations over the centuries. Significant numbers of people in the country speak Polish, Yiddish, Rusyn, Belarusian, Romanian or Moldovan, Bulgarian, Crimean Turkish, or Hungarian. Russian is the most common minority language. So we shall see how cohesive the nation remains in absence of a threat from Russia.