I wonder if curiously, the way the battlefield has evolved, the best thing that can happen for the Ukrainian side is for Putin to keep pushing for more territory. The advantage in this war seem to be heavily tilted to defense, so it seems the highest probability for the Ukrainians to be able to attrit the Russian forces to the point of collapse is if the Russian keep extending themselves. If they were to consolidate and force the Ukrainians to try to push them back, they might have a better long term outlook. But so far from what I have read, Putin's still demanding more gains.