The more they grab though, the stronger their position at the international negotiation table, to achieve what you describe as their goal. "You want us to withdraw from everywhere?? Nah ... The maximum we are willing to go for is withdrawing to the 'new republics'." And then some inconsequent negotiations may grant them that, thinking "Well it will be just as before then." And by agreeing to such a bad result to stop the bloodshed, Putin has got what he originally wanted. Maybe that is his long term goal and the redt is show for the west. An act to spread as much horror and terror as possible.