During the Cold War there was a time in the 50's when the Soviet Union was running neck and neck with the US. Famously they were the first to launch a satellite. A few decades later and the technological gap was so large that the US seemed to be from an alien world compared to the Soviet Union.
You shouldn't believe everything you read.
Only for consumer tech, not military. Also, as the war in Ukraine proves, you don't need cutting edge chips to inflict worlds of pain on another country, but 100+ year old tech of mortar cannons and shells are more than enough.
Plus, high tech Russian weapons use commercial off the shelf chips from the west that you can't stop them buying off the free market anyway. An Arduino or Raspberry Pi could very easily guide a bomb. You don't need an Nvidia A100 for that.
Worth noting the difference in scale between Russia (1.3m active personnel) and Ukraine (0.2m active personnel), the West are not directly participating in the battlefields (due to nuclear threats), and that Russia is connected to Ukraine by land.
For the Chinese case, the US has been very clear about sending armies to defend Taiwan, which is separated from China by sea.
So a technological gap can be a sufficient deterrent for the Chinese case, while less so for the Russian case.
So they would go from attempting to conquer a new piece of land via conventional war that they can withdraw from at any point if losing to facing destruction.
They've lost wars like vietnam and withdrawn after declaring victory, so it's not like they are suicidal if they dont get their way.
Russia threatens to use nuclear, even without being hit with nuclear.
Later they were unable to do things like manufacture propellers for their submarines [2]. Not to mention the Gulf War.
[1] `The state of scientific computing was particularly backwards, with the CIA commenting that "to the Soviets, the acquisition of a single Western supercomputer would give a 10%–100% increase in total scientific computing power."[54]`
[2] https://en.wikipedia.org/wiki/Toshiba%E2%80%93Kongsberg_scan...
https://www.reuters.com/technology/nvidia-may-be-forced-shif...