Ukraine's ascension to NATO would show Russian Pres. Putin that the continued occupation of Ukraine will leave Moscow lost on the international stage. As Ukrainian Pres. Zelenskyy has said, Russia must recognize that Europe has borders and independent states, and that every nation has the right to choose its own future.
Dragging Ukraine into the NATO military alliance would exacerbate the issues that started this whole conflict in the first place, particularly given NATO's cultivation of Ukrainian nationalism that resulted in a violation of the rights of the country's Russian-speaking citizens. It's impossible to achieve a fair settlement without eliminating the route cause of the conflict.