The military leaders who ordered troops to garrison in illegal areas should be arrested, charged, and tried in an impartial court.
Any Ukrainian soldiers who killed POWs should be arrested, charged, and tried in an impartial court.
War crimes are not ok, and have been committed by both sides. Any perpetrator of a war crime, regardless of allegiance, should be tried and appropriately punished if convicted.
Putin can end this war by pulling back his troops. I do not support the invasion of sovereign nations, just as I don’t support the violation of an individual’s sovereignty over themselves.