I agree Yva. Putin is a despot, like many others, and he's tried to take advantage of the situation - he's one in a long line of would-be Tsars. But the underlying situation at the cultural level is much more complicated and is based on 150 years of threat and invasion of Russia from the West, starting with Napoleon, and going back many hundreds of years before that to the times when they were subordinate to the Mongols and to medieval threats from the West. It's no excuse for what they are doing in Ukraine now, but we'll never be able to work out what is happening and form pragmatic and peaceful policies in that region if we don't try and understand the fears that drive the ordinary people there. Of course the despots take advantage of them and channel the fear for their own ends - and like all bullies their fear is expressed in terms of threat, boasting and self-inflation. The only language they seem to know is mass murder when they are back to the wall. It wouldn't surprise me when all this is over that he's caused the deaths of as many of his own folks as he has amongst the Ukrainians.
I'm no expert either, but reading the history of the Napoleonic invasion of Russia, the impact of the two 20th Century world wars in that region, and looking at the history of folks like Alexander Nevsky and Ivan the Terrible is quite an eye-opener. Reading up on the 1000 year history of the Orthodox Church in the region is also an eye-opener.
Perhaps an analogy to what is going on in Ukraine - as a thought experiment what if Texas and California became independent from the United States, then started looking at a possible link up with Mexico whilst at the same time Mexico was exploring the idea of an economic and military alliance with China. The feeling of threat in the USA would be palpable. I suspect this is very close to how the Russians feel about the situation in Ukraine.