Yes, but if they do this, Ukraine may kill hundreds of thousands, if not millions, of people in the previously occupied territories, including Crimea. Such an outcome is obviously unacceptable to Russia. The Ukrainian fascist paramilitaries have seen the pro-Russian separatists as subhuman for many years.

Yeah the west and Russia where saber-rattling. But Russia choose to act and it.

Russia chose to act on it because it was quite literally the last moment they possibly could have done so, given the rhetoric at the time of Ukraine potentially joining NATO (and even Zelensky asking for nukes!). NATO attempted to provoke Russia into war for decades by marching their military forces towards Russia's border and establishing anti-Russian governments in ex-Soviet countries. Many in Russia accuse Putin of cowardice because he didn't act sooner against NATO and Ukraine and getting them into this mess now when almost every country of note has been converted into NATO vassals, far from opposing him for being a tyrant or whatever. I'm not saying that this makes those civilians correct, it's merely outlining how Russia "choosing" to act on it might not have been a random act of cruel violence by Supreme Dictator Putin but instead an action informed by a whole bunch of factors and that the Russian government has generally been pretty non-violent up until this point even when America is directly spitting in their face and adding more and more countries to the Fuck Russia Club. The Russians might say that they heavily disagree with these countries having NATO membership because it imperils them - and it very obviously does - but when the Baltic states joined NATO for example, Putin didn't march his army to conquer them in retaliation. When Finland joined, he didn't send the tanks over the border. It was a measured decision by Russia to intervene in Ukraine, and it is important to have understanding beyond cliches.

The thing is putin will only use diplomacy on his on terms, and these terms alone will threaten the existence of Ukraines souveränity itself.

This is untrue. At the beginning of the war, in April 2022, Russia and Ukraine almost made peace along the lines of Ukraine regaining Kherson and Zaporozhye, and ceding control of the Donbass, which they already didn't really control anyway due to the Donbass War that has been ongoing since 2014. Ukraine was also allowed to join the EU, but not NATO. The West - in the form of Boris Johnson - came along and told Zelensky to not make peace with Russia, and so the deal was cancelled. We know this because Putin showed off this unfinished peace deal to various African politicians earlier this year. Ukraine could have kept millions of people inside their borders and hundreds of thousands of men alive, and kept two oblasts that they now do not own, if they had taken this deal and ignored the West.

Even so, Russia stated numerous times that they were still willing to make peace. It is Ukraine that does not seem to want it, because their terms are always "If Russia completely withdraws their forces then we will begin to talk," which is an absurd condition no matter whether you're in the right or wrong in any geopolitical or military situation. You see this a lot in history, where countries say "Oh yes, we won't declare war on you, you must only agree to a set of conditions that we know you will never accept," because it makes them look slightly more reasonable to other countries for not just marching in there. I'm sorry, Ukraine could be the most perfect, utopian society that has ever graced the world and Russia could be the most barbaric, backwards, evil nation ever seen in world history, and I would still see Ukraine's demand for Russia's total retreat as ridiculous.

And victim blaming is never ok, even when you think the victim is an asshole.

The question of who's the "victim" here depends on how far you're willing to look back in history, what you think are relevant facts about the situation, whether you believe the 2014 coup was in fact a coup, whether you believe that Ukraine is plagued by fascist paramilitaries like Azov or whether they're cutesy fun girl scouts, and quite literally hundreds of other things. I'm not even willing to be automatically contrarian and say "Actually, Russia is the victim and NATO is the aggressor!" because that's also not correct, the situation is way too complicated. This isn't Harry Potter vs Voldemort.