I suspect Russia wants to drive a good percentage of Ukraine’s population out of ukraine as refugees. This is why they have not and will not close the western border of ukraine.
Russia’s conduct around built up areas of ukraine suggest to me they are not so much there to attempt to take the cities, but to simply fight over them so as to make them unfit for civilian occupation. This will dislocate the most highly educated and productive of ukraine’s population, turn them into a homeless population of refugees. the destruction of these built up areas will also destroy the postwar economic foundation of ukraine, giving these tefugees nothing to return to comparable to their prewar standard of living.
Yes, a fraction of the dispossessed will turn into a hardened insurgents or join what is left of ukraine’s armed forces to make the russians pay for this. but a much larger percentage will likely simply seek to escape ukraine by emigrating as refugees because they can see the destruction the dispossessed them would also leave few economic opportunities for them to look forward to after the war. very small percentage of these refugee emigres, once they settle in europe or elsewhere, would ever return. So the result is any post war ukraine will be deprived of much of its educated and skilled classes.
So basically russia, having failed to quickly topple the government of ukraine in a cou de main and thus convert an intact ukraine into a client state, seems now settled on the strategy of essentially destroying the infrastructure and demographic fabric of ukraine to prevent it from being able to survive or revive as an effective independent state that has the wherewithal to threaten russia’s interests through collaboration with russia’s enemies.
If i am right, then This is no longer a relatively clean war of shadow boxing between armies. It is turned into a war of ethnic cleansing by a different name, similar to how WWII was fought on the eastern front, and how the european wars of the age of reformation between 16-17th centuries were fought. the purpose of the war is no longer to achieve a narrow political objective, but to fundamentally alter the demographics to achieve long term geopolitical objectives.