Ukraine expected US / Nato to protect them from Russia. Russia knows that NATO presence in Ukraine will be a risk to Russian security, even without conflict with Ukraine. They will not allow NATO forces deployed close to their borders. Ukraine is paying the price for US/ NATO strategy. Basically, it’s for those who didn’t get it. The United States is launching yet another war in which it is the third wheel.
A technology divide, in my opinion, is the only thing that can genuinely create a world war. It could happen if one of the nuclear powers develops a sense of invulnerability and believes they have acquired technological superiority that allows them to safely annihilate their adversary without fear of retaliation.