One option for Putin is to withdraw all his forces to the Donbas, saying that all other offensives were merely feints or designed to attrit the Ukrainian army. He can sell this to a disinterested/ ill-informed domestic audience as job done. We have two new provinces and Ukraine is no longer a threat. He will then hope that by going on the defensive he can - a. Preserve his forces, b. Hope that the strength of support for Ukraine from the West wanes and c. Portray Russia as the innocent party trying to defend itself against foreign aggression. He probably already knows that if he continues with his present strategy he’s likely to lose everything