If you ask me, its only the USA that is obsessed with genocide and pre-emptive first strike insta-win type scenarios. Biden calling "genocide" on a white nation is a really messed up thing to say. It would be like saying China invading Taiwan to be genocide.
Realistically, Putin would have an incredibly hard time trying to maintain control over the populace of Ukraine if he accepted a simple surrender. 10 years from now, he would probably have to quell uprisings. Again, if he simply flattens the cities - he can scare all the farmers away and simply replace them with Russian farmers. Zero worries about uprisings in the future.
https://www.bbc.com/news/world-60555472 Lets say if Putin can get to roughly 15 million leaving Ukraine, then he might be able to declare victory simply by civilian displacement. You can definitely win wars just by the other guy leaving and never surrendering. Taiwan would not be defeatable in this manner simply because it is an island and boats only can evacuate at snails pace.
In North America, the cities are quite valuable. In Ukraine, the farmer fields are far more valuable.
Karkhiv is next.