Russian strengths and weaknesses in military technology
There are Russian strengths and then there are the weaknesses.
For example, Russian engines and SAMs are pretty good.
However, Russia could never develop compact electronics to install an AESA radar on a destroyer. The best that the Soviet Union/Russia could accomplish was an AESA radar on an aircraft carrier.
Also, it is clear to all that the Russian T-50/Pak-Fa third prototype (after two years) embodies all of the stealth design flaws of the first prototype.
In conclusion, the Soviet Union was competitive for a few decades. However, it had weaknesses (e.g. electronics, advanced materials, systems integration, etc.). Today's Russia is clearly a lot weaker than the Soviet Union in terms of resources available for military research and development.
No amount of propaganda can convince objective observers that Russia is not falling behind the U.S. and China. Russia lacks the tools (e.g. supercomputers) and resources to compete with the U.S. and China.