10% of the Soviets celebrated MIG-15 fighters were lost to fuel tank implosions, a direct result of failure to test.The Russians had great designs that just didn’t work well in combat. I suspect China will be the same.
The Soviets never had the benefit of (cyber)stealing/trading/learning Western technology that the Chinese now have. While transposing excellence in small commercial goods to high-end military systems will take time, it puts the Chinese in a different league compared with the Soviets.
I don’t remember having one Soviet-built product ever in my house, do you remember if you had any? Now, most of the electronics I use have something Chinese about them — whether I like it or not. And their quality is also improving.