Sorry to say, autocrats do not withdraw from a conflict like this regardless of attrition. Their power is their legitimacy and defeat is a threat to both their rule and probably their life. I mean look at how much flak Biden took withdrawing from Afghanistan despite being able to say that it was a horrible idea and someone else's fault.
This is a little different from Afghanistan and Iraq though, Russia's security concerns are valid and probably ameliorated by Ukraine as a failed state (as opposed to a NATO aligned state) so conquering and pacifying the country is not necessary.
The only real humanitarian solution is a diplomatic solution. I wonder if written guarantees that Ukraine and Georgia will never join NATO would be enough now honestly.