If it's not such a far away conflict then why isn't Putin looking for a way to stop? If anything the war shows how little Putin cares about his own people, even those close around him and how willing he is to spend their lives to burnish his legacy. In that case why would you think that any backing down on Ukraine leads to anything other than him or his successors wanting to swallow more?

Personally I don't see any real chance of nuclear escalation over Ukraine on both sides. The war needs to end but to do that Putin needs to be given a way to deescalate and claim a win at home. But that can only be allowed to happen if Ukraine is made safe and secure once again and if Putin is willing to swallow that. And I see no evidence of that being true.