Presumably it would be an impossible cognitive dissonance for him to acknowledge (to himself) that actually it would be justified for Ukrainians to turn their back from Russia and join the West. Those people must be misguided/contaminated or defectors, and surely those who can’t be turned back can only be a small minority.

Beliefs like that are not standalone, they fit into a belief system. You can’t overturn them unless you overturn the whole belief system. Seemingly absurd beliefs can come about by the psychological necessity of keeping the belief system consistent. Putin’s belief system probably was formed during his KGB time in the 70s and 80s, and has continued to develop and has become stronger and harder to change since then. He’ll be 70 in October, unlikely to fundamentally change his mind at that age.

Not KGB. This dude and his books https://en.wikipedia.org/wiki/Aleksandr_Dugin Also run through this article and try to correlate it with todays reality https://en.wikipedia.org/wiki/Foundations_of_Geopolitics

Not "not KGB", I think -- my guess would be that dude and his books and the KGB. From what I understand of their views, Dugin's fit in pretty well with the KGB's.