One part of Ukraine as it existed prior to 2014 is fighting for the right to force another part of Ukraine to remain under their domination. The Kiev regime insists that the post Soviet boundaries be enforced, and that Kiev remain in charge of all of it.
Even when you go to the region around Kiev, it's not clear how much support the Kiev regime really has at this point, even in their own capital city.
The many thousands of men being conscripted and press-ganged are not necessarily "fighting for Ukraine" they are unwillingly forced to participate as soldiers or face terrible consequences.
Now that Zelensky has cancelled elections, banned opposition parties, shut down opposition press, and even seized property of the largest religious denomination in the country - it seems disingenuous to claim that "Ukraine" is fighting for this or that.
The Zelensky regime is fighting a war with their conscript army. The American people have been press-ganged into paying for it. One cannot help but wonder how important the obvious bribes the Kiev regime has paid to American politicians (and their families) is in keeping that funding going.
The war began as a Civil War in the Donbas. So, that also means there are lots of people who were (politically) "Ukrainians" who are fighting against the Kiev regime. That battle started shortly after the coup d'etat in 2014 which overthrew the government.
Some people in Ukraine are fighting to maintain the post-Soviet borders of Ukraine.
Other people in Ukraine are fighting to leave the political union with the Kiev government, and move the borders. Until 2022 this was a civil war, then Russia entered, so it's more a regional war now. But the fundamental aspect of it hasn't really changed that much. .
Those complaints and criticisms are over-stated and are not a valid basis for Russia to invade Ukraine — and far worse can be said truthfully as to Russia.