While Russia is unlikely to occupy all of Ukraine, they're certainly capable of demilitarizing Ukraine and putting in a Russia friendly government in charge of whatever remains of Ukraine in the end. Ultimately, the core motivation for the war was to keep NATO out of Ukraine. Stopping short of that would not solve the underlying problem.
It's worth keeping in mind that this was a war of attrition. Everybody who was motivated to fight against Russia signed up to join the army early on. Most of those people are now dead. The AFU is now reduced to grabbing people off the street and forcing them to fight. Most people who are left in Ukraine just want the war to be over and they don't actually care whether Ukraine is going to be under Russian or western influence going forward. The only option NATO has left at this point is to go directly to war with Russia.
While Russia is unlikely to occupy all of Ukraine, they're certainly capable of demilitarizing Ukraine and putting in a Russia friendly government in charge of whatever remains of Ukraine in the end. Ultimately, the core motivation for the war was to keep NATO out of Ukraine. Stopping short of that would not solve the underlying problem.
I think that's actually going to be pretty difficult. It would be a true triumph of counterintelligence to pull that off.
It's worth keeping in mind that this was a war of attrition. Everybody who was motivated to fight against Russia signed up to join the army early on. Most of those people are now dead. The AFU is now reduced to grabbing people off the street and forcing them to fight. Most people who are left in Ukraine just want the war to be over and they don't actually care whether Ukraine is going to be under Russian or western influence going forward. The only option NATO has left at this point is to go directly to war with Russia.