Back at the beginning of the arms race, the US believed Russian propaganda that they had significantly more nukes than the US was capable of producing.
By the time the US had around 4000 nukes, later intelligence revealed Russia had 4. The US decided to maintain the policy of the arms race as it was very beneficial to the defense industry and research.
The cost to develop and maintain a working thermonuclear weapon is enormous, let alone fission bombs. Russia never had the resources to maintain an arsenal the West isn't capable of intercepting. You may recall the "Iron Dome" missile defence system that was removed from Europe.
The rocket platforms are expensive enough. The nuclear material requires time, maintenance, and a fuck load of power to produce.
I get the fear. China can do it, they have all the resources and knowledge to. Same with India.
Facts of nukes help:
Tritium has a halflife of 12.3 years. Meaning after 12.3 years, the amount of tritium in a nuke is half. the 500lbs of tritium in the 60s is now 35lbs today. Obviously I dont know how much is needed to make a nuke, but it's not easy to concentrate tritium well. The most effective way is replacing control rods in nuclear reactors with lithium rods. But that's not the real issue. That's relatively minor.
The problem is weapons grade uranium or plutonium. You need to enrich those to very high % of U-235 to get a big enough blast to trigger the fusion reaction. To do that, enormous, power intensive centrifuge facilities are required. And it takes a long time to produce enough for a fission bomb.
Given that Putin operates on wealth, and the shit state of the Russian military? They didn't maintain any operational nukes after the Soviet Union fell.