Putin sees Ukraine as a vassal state, that belongs to Russia. He believes that allowing it the illusion of independence was a mistake, and he intends to reabsorb it into the Russian Federation empire.

All vibes-based conjecture written with the air of a young adult novel. Contrary to what you might hear on the news, Putin is not the Russian Federation, and the Russian Federation is not an empire. Countries have classes, contradictions, material interests and pressing issues. They are not YA antagonist factories controlled by one Big Bad Guy, and any analysis that treats them as such will inevitably fall flat. You seem to be starting from the conclusion that Russia is an empire and working backwards from there. Do you know what an empire is? Also, this war is partly about NATO on Russian borders. If Russia absorbed all of Ukraine, that would result in both a nazi insurgency and....NATO on their borders. It would be completely self-defeating and against their interests, and this is obvious to anyone who even thinks about it for five seconds. They want Ukraine to be a demilitarized buffer state that their rivals pay to maintain, not some incredibly expensive hostile medieval vassal that they have to occupy for decades.

Ukrainians on the other hand, do not view themselves as Russian, or even “belonging to Russia”.

Except the ones in eastern Ukraine who absolutely do, and who the Kiev coup regime has spent ten years ethnically cleansing. They voted to join Russia, they voted to ask Russia for help, and Russia obliged.

It is not the same as a single people having a civil war.

The Vietnam War was not a civil war. It was one half of the country being occupied by the US empire and pitted against the other half, while western media pretended that their Frankenstein creation, the Republic of Vietnam, was a legitimate government with popular support that was being unfairly attacked by their evil communist neighbor. This has been the US playbook since the beginning of the cold war: stage a coup, suicide bomb their new puppet into a geopolitical rival to start a highly profitable proxy war, and then play the role of victim forced to respond. It's the geopolitical equivalent of I'm-not-touching-you. This is what they did in Vietnam, this is what they did in Korea, and this is what they did in Ukraine.

It is a fight for independence from a larger colonial force, intent on destroying their cultural independence and stealing their land and resources.

This is the most "source: trust me bro" thing I've read in a while. It's obvious that you don't know what half the words you're using even mean and are throwing them in for rhetorical effect. Colonialist? Destroying their cultural independence? Brother, you're just saying shit. Tell me how Russia is a "colonial" force. Where are their colonies? Tell me what they're doing to Ukranian "cultural independence", whatever that means. These are weasel words.

By the way, the Ukranian coup government actually did engage in cultural repression by outlawing the Russian language in schools, effectively barring like a quarter of all children in the country from receiving an education. This is in the context of an ongoing ethnic cleansing campaign that killed 13,000 civillians starting from 2014. This is what western media outlets say you should be defending. The same media outlets that swore up and down that Hamas beheaded 40 babies and there was no genocide in Palestine. I don't know how to make it any more clear that you are being lied to by fascists about who the victims are here, which is a fascist's favorite thing to lie about.