Let's talk about whether Putin really was acting as a strategist and master chess player back when he took Crimea in 2014 or invaded parts of Georgia in 2008-- because I do not believe he was. Instead, he set himself on a path than almost inexorably led to where we are today and blew up bridges behind him. I am tired of the "offramp" talk, but to push the analogy-- he has driven into a cul-de-sac and the only way out is to turn around or destroy a house and hope you can plow through to another street.
It's important to see what the 2008 "Bucharest Pledge" really was-- it was a no-time frame "promise" that Georgia and Ukraine would get into NATO. Now, NATO can do expansion pretty damn fast when it wants to, which Putin had seen a couple times since the collapse of the Soviet Union. He also, as the head of a formidable foreign intelligence apparatus, was clearly aware that multiple NATO states had to be prodded and poked into making a toothless promise and would have been happy to continue kicking the can down the road as long as there was a viable reason. And buddy, Ukraine could ALWAYS be counted on to give you reasons to doubt its competence or readiness to enter the Alliance.
By fundamentally misreading Maidan in 2014-- accepting it as a foreign-backed coup designed to install a hostile regime-- Putin closed off the entirely more sensible opportunity of letting the anger burn off, letting Ukrainians fight amongst themselves and steal from each other, and most likely swinging back to Russia after one or two more cycles just like what happened after the 2004 Orange Revolution. He could taken plenty of over and covert steps to encourage this process along and could have easily cast himself as the more sensible, richer, stable party and given Berlin and Paris all the reason in the world to keep integrating with Moscow, slowrolling Ukraine into NATO, and generally letting Ukraine be Ukraine-- divided, unreliable, and neither here nor there. And by almost any predictive measure, that's what would have happened.
Instead he annexed Crimea and gained almost nothing but national pride. He started a war in the east and risked his credibility and prestige for some extraordinarily unreliable local friends that he never wanted anyway. He pushed friendly NATO states into the unpleasant position of having, at least reluctantly, to routinely denounce Russian aggression and foreign policy as a matter of course. He picked a battle of wills with the United States that was always unwinnable ("promise you won't ever try to be Ukraine's BFF!). And he ensured that generations of Ukrainians, no matter how corrupt or chaotic, would always be corrupt, chaotic, and relentlessly hostile to Russia.
Maybe most importantly-- his only real move was to continue to ramp up tensions or aggressions, or to lose openly and publicly. He decided for himself what "winning" should look like, told the world and the Russian people, and put himself in the position of going for the W or taking the L. No more playing for the tie. And it looks like he is taking the L.