NATO/Zelensky are of course reluctant to go ahead because an application to join would reinvigorate the civil war. They know the cost of giving the middle finger to Ukraine's ethnic Russians and would prefer to wear them down gradually while blaming the whole shitstorm on Russia.
Russia (and ethnic Russians within Ukraine's borders) would prefer Zelensky was kicked out and replaced with another Yanukovych who would kickstart the process of deintegrating from the European/American sphere of influence and reintegrating into the Russian sphere of influence.
Ukraine could do a better job of playing the two great powers off against one another a la Tito/Yugoslavia, but instead it swings violently between being ruled by a bunch of corrupt Russian-aligned oligarchs to being ruled by a bunch of equally corrupt European/American-aligned oligarchs.