Russia can't win anymore. Their only chance was the "take Kiev in 3 days" plan. That failed miserably and now the question remains how long can Russia hold out in Ukraine. Ukraine will never stop fighting until the russian occupying forces leave their sovereign territory. Similar to the Taliban in Afghanistan. No matter how long it takes. One year, 3 years, 20 years. At some point, it'll become too expensive to occupy a warzone. Russia and USA faced that problem in Afghanistan. But on the other side if you fight for your homeland, you have no timelimit, you are patient.
Russia tried to destroy Ukranian morale with their missiles and energy terror, but that also failed and even strengthened their resolve. There is nothing Russia can do anymore except from go nuclear, which they won't do, because then Nato would immediately create a no fly zone in Ukraine.
So the only question is, how long the war will continue and how many people have to die until Putin acknowledges that he can't control Ukraine and leave them as they did in Afghanistan back in the days.