I really don’t think Ukraine and Zelensky are fighting for anyone bar Ukraine. It is no longer a Cold War front line, and I don’t think Putin has any illusions of going any further west than the Polish border. Right now, he would gladly settle for the Donbas and lick his wounds.
Ukraine has fought, with the aid of the U.S (and some cash from the big talking but little risking EU and UK), both creatively and heroically.
I think Zelensky was quite corrupt before the war, but I do think that he has been quite a heroic war leader, albeit lacking the diplomatic skills to keep a truculent U.S onside.
However, realistically, it is now time to settle and both sides have to be realistic. Will Putin profit from his aggression? Yes, although it has cost him a lot of blood and treasure.
Endlessly extending a stalemate isn’t of any use to anyone.