Those are two fundamental questions.
On the point of the war not going the way people on either side thought it was going to go, wars generally tend to do that. World War I started in 1914 with one concept and ended in 1918 with a completely different concept.
Yes, this war was going to be a short, snappy one. The Ukrainians and the Russians were still meeting in March 2022 to discuss the Minsk II variation of a settlement—well into the war, a few months in. We don't know where this is going to end up now, but it's certainly nowhere near what anyone thought. Intelligence had it wrong on both sides, as it often does.
On the lessons learned, we're learning that modern warfare is, in some ways, taking lessons from the last year of World War I, when there was a strategic stalemate and what are called storm troopers. I don't mean the Nazi thing. I mean the small units. Canadians were very innovative, as were the Germans, in having small units that would try to break through the stalemate and advance on each other. What the war is showing us is that with modern technology, if you move, you're seen and you're killed. Therefore, you have to figure out ways to advance your position without being seen and killed, and that means small unit attacks.
That's why when people say Ukrainians may be starting this offensive, they may be but we don't know about it, because there's not going to be a big wave over the top, like there was in the early part of World War I.