Russia has physicists the equal of ours, they may have had some espionage info to get started, but they are quite good on their own.
In some respects Russian scientists are better, in others not as good.
They are behind in computing, but ahead in math.
Sure, they have good physicists, but the stuff has to be made by Russians.
But do they, the Russian government, pay attention to their work? The old Soviets blew off their own physicist’s theory on stealth aircraft and he ended working for Lockheed on the F-117 project. Lockheed used his published work to propose their design on the project even though they were not invited to submit (only Boeing and Northrup Grumman).