Not to mention that, being a decently sizable country, making them is really more a matter of motivation to put in the resources and deal with the diplomatic effects than it is capacity ultimately. Like, North Korea was able to build them with a fraction of the population and economy and as even more of a pariah state, the technology has existed for just about 80 years at this point and while details of the specifics are secret, the basic gist of what they require is well known. Basically any country that isnt a microstate probably could build a few eventually, if they really wanted to spend all the money