Actually a good write down, I think it's not to far from the mark as far as Putin's perspective is concerned.
Since more than one thing can be, and usually is, true at the same time, I think one part is exactly as you described. The other is that Putin simply really wants Ukraine back in the fold, among other countries that used to be part if the USSR.
Again, all of that is just a, potential, explanation. It is not, by any means, an excuse or justification.
Here's where I differ and as much as I detest Russia's actions and Putins kleptocracy, he is a chess player, highly rational and calculating.
The idea that Putin wants to reclaim the former USSR border is ludicrous to me because it would mean raiding his own coffers.
He comes across as an opportunistic and a highly adventurous individual focused on wealth building.
I don't know if you read Alex Litvenenko's book but Putin's roots, his associates and friends, wealth was his end goal from the start. Why someone like him would be considered to be capable of empire building (when he could barely contain Chechnya) is beyond me.
Putin is a thug and he cares more about his wealth than the interest of his own country, and the #1 threat to him isn't sanctions but Hague trials.
There is overwhelming evidence that Putin was responsible for the apartment bombings (https://en.wikipedia.org/wiki/Russian_apartment_bombings), and if the truth came out, it wouldn't be his own people that take him down alone but the combined threat of NATO military action and an emboldened local populace.
Again I am not a psychologist but someone this selfish and material focused (his stupid Versailles 2.0 project that went to crap) is simply NOT interested in restoring USSR glory or anything like that but rather like any good capitalist, obsessed with maintaining his wealth.
Since more than one thing can be, and usually is, true at the same time, I think one part is exactly as you described. The other is that Putin simply really wants Ukraine back in the fold, among other countries that used to be part if the USSR.
Again, all of that is just a, potential, explanation. It is not, by any means, an excuse or justification.