solarz
Brigadier
They are going to end up with a hostile Eastern Europe and NATO on their borders even if they annex all of Ukraine. There is no world in which Russia comes out of this without NATO on their borders. Their best course of action was to show the world how toothless NATO is by executing a quick and easy regime change in Ukraine, but that’s already failed; best they can do now is to force NATO to the negotiating table by a string of victories that show the Russian bear still has teeth.
The ramifications of a clear Russian victory in Ukraine, whether that's full or partial annexation of Ukraine territory, goes far beyond to that. It would result in a severe blow to NATO prestige.
In hindsight, both sides miscalculated. Russia thought they could get NATO to back down with a quick victory, and for a few days NATO was prepared to write off Ukraine.
However, poor Russian logistics and stronger than expected Ukrainian resistance made NATO see an opportunity to drag Russia into a military quagmire, so they started sending in military support to Ukraine, but they've invested so much into the theatre that their own reputation is now on the line.
Such are the vagaries of war.