There is quite a few "russia experts" on Twitter stating all of russian nukes are rusty piles of metal and most certainly won't fly. The current propaganda is the closest I've seen to what can be described as "being high on own farts"
Given the evident shape of Russian forces, I wouldn't be surprised if over half of their missiles couldn't deliver a warhead. But they've got thousands, so if even 25% are viable that's still more than enough to keep MAD relevant.