Also a lot of the late Soviet Union military technology came from Ukraine, plus their military were also trained in the same kind of school of thought as Russia and still know it.

So it makes sense that, when push came to shove, the Ukranians would fast come up with asymetric war solutions against Russia, that Russia wouldn’t be as fast in effectivelly countering them and Ukraine would be quicker at developing new or adjusted solutions once Russia found a counter (or, more generally, that Ukraine would remain ahead of Russian in the cycle were each side develops a counter to the other side’s counters).

Had Russia’s initial blietzkrieg attack worked, it would’ve been a different story, but at this stage it makes sense that Ukraine has the technological edge, not just in the weaponry it gets from the West but also in their own weapons development, especially now that it has much better AA to protect the installations far away from the frontlines working on weapons tech.