Is "the" USA or "the" Philippines, "the" UK or "the Netherlands, a country or a region? well it's both
Ukraine in it's Slavic origin Ukraina means actually Borderlands. So to say "the" Borderlands or "the Ukraine" is absolutely correct.
The issue is that Ukraine associates "the" with the Russian usage of "na"- meaning an unbounded territory and using "v" to describe a bordered/bounded territory. (which has actually nothing to do with using the article "the"in English or "die" in German).
As such the Russian Federation instead of saying "na" Ukraine is correctly referring to the Ukraine now as "v" Ukraine, (the "Bounded" Borderlands) making use of an article just as in German with the article "die" Ukraine.
I find this just silly - if they take nationalism for so important then maybe they should look for a new name, if they can't handle the historical origins of their countries own chosen name, instead of degrading other peoples languages respectively it's grammer.
I shall henceforth "in order to avoid issues" and to honor their history refer to them as "the Borderlands"