F22 and F35 radar is very hard to detect and quite likely the F22 or F35 you are fighting will be useing another F22 or F35s or AWACs radar.
Chima is simply copying Russia Technology and
In the real world Russia was already far behind the West when it came to computers, communications tech, radar and avionics. This gap widened after the fall of the Soviet Union when Russia's economy tanked into the gutter and R&D expenditure was almost zero.
Even today, Russia's R&D spending is FAR behind that of the US. Let's also not forget that Russia is not a major player in the computer, tech or communications industries. The PAK-FA is also being developed on a fraction of the budget of the F-35 and the F-22.
Just because the PAK-FA is newer doesn't mean that the Russians are likely to overcome a colossal deficit in R&D base, development budget and experience. Maybe it would be possible if Russian scientists and engineers were somehow vastly superior to their American counterparts but there is scant evidence of that. Indeed, Russia is struggling to combat "brain drain."
Even India spends a lot more on research and development then Russia. US 405 India 36, Russia 23