This is part of the propaganda. I've read multiple analyses, very cogent and well-sourced, that concluded that what Putin wants is not just to conquer Ukraine,

This is part of the propaganda. I've read multiple analyses, very cogent and well-sourced, that concluded that what Putin wants is not just to conquer Ukraine, but to reassemble the USSR, or the Tsarist Russian Empire before it, with him at its head. He sees the fall of the Soviet Union as a stain on Russia and on him personally, and he wants to restore his/its "dignity". As part of this, he believes that Ukraine is Russian, and that any Ukrainian who does not see themselves as Russian is wrong, and likely either an American-sympathizing traitor, or mentally ill. "He does't want Ukraine to join NATO" is true, of course, but in the same sense as "he doesn't want to lose his power." He wants to keep both of those things and gain much more. Making it all about NATO is 100% part of the propaganda he has been spreading.