Putin can't have the US. He knows that too. He's been trying to expand very slowly without touching NATO. This Ukraine invasion has been in the works since at least 2014 or even earlier.
What's going to happen is he's going to try to starve his country to death over a military adventure to try to save face, then he's going to have a lot more problems inside than outside.
His miscalculation is that he thought the world would react like it did in 2014. He was wrong.
At this point, I still think he will take Ukraine, but the cost is going to be extremely severe.