You are correct. I owe Zelensky absolutely nothing.
Ukrainians are fighting and dying against Russian expansionist aggression.
America and The West have chosen to support Ukraine to resist Russian aggression.
It has absolutely nothing to do with “owing” anybody anything.
Russia vs. Ukraine is analogous to America trying to retake a breakaway Texas. Did you forget that the Ukraine has been part of Russia since 1654, over 334 years before the fal of the Soviet Union? In 1654 the Cossacks signed the Treaty of Pereyaslav with Tsar Alexis, the second tsar of the Romanov dynasty. This saw the Cossacks break with the Polish-Lithuanian Commonwealth and formally offer their allegiance to the Russian tsar. The USSR would later style this as an act that reunified Ukraine with Russia, bringing all Rus people together under a tsar.
Read a few history books and get a clue.