Russia will never tolerate Ukraine as a member of NATO

That's what this current Ukrainian war is really about. Russia cannot, and will not tolerate NATO nuclear missiles based on Ukraine's northern border with Russia. The entire nation of Russia would be totally under NATO's thumb. Which, of course, is precisely what NATO wants! But, not Russia. Effectively, this would amount to a similar situation to one in which China and Russia made Mexico their military partner, and positioned Chinese and Russian nuclear missiles all along the Rio Grande. How would the Americans like that? Not very much. We all remember how President Kennedy went ballistic about the missiles in Cuba. So, really, is it so very difficult to understand the Russian position about Ukraine having NATO membership? What the Russians are doing now is building up impregnable fortifications in Ukraine, and forcing the Ukrainians to take massive casualties in unsuccessful efforts to penetrate these defenses. This is wasting Ukrainian manpower and NATO resources in massive quantities. Enough so, that NATO is already tiring of wasting their efforts, and the alliance against Russia is becoming very shaky. Of course, if NATO wishes to continue spending massive amounts of money to support a losing cause, Russia is prepared to continue their efforts. Russia will never give up, and, Russia cannot lose. Remember, this is more of an existential battle for Russia than for the West. Russia doesn't particularly want to invade Western Europe, and has no reason to do so. They just want Ukraine under their control. And, they are gradually getting Ukraine under their control, despite the West's best efforts.