My prediction:
About this time next year active hostilities end with Crimea formally seeded to Russia but all the other border’s returned to the 1991 lines. Russia gets to a point where the effects of the war are felt by the average Russians in a way that Putin can’t ignore while at the same time the Alliance supporting Ukraine get donor fatigue from their population in a way that Western politicians can’t ignore. Ukraine is forced to accept a compromise on their objectives for continued support.
Russia gets to save face with a “win” in Crimea, a place with strong historical ties to Russia. Ukraine gets security guarantees including a fast track to join NATO.
Nobody will be happy, so this IMO is the mostly likely outcome.
The nightmare is Putin uses tactical nuclear weapons in an “escalate to de-escalate” strategy to force regime change in Ukraine. He will be banking on the West to not have the stones to directly engage him, an uncomfortably possible outcome…..