That may be, but Putin’s spokesman is quoted here as saying up to 100 megatons.
“There’s no way of stopping this underwater drone. The warhead on it has a yield of up to 100 megatonnes.”
https://www.irishmirror.ie/news/irish-news/vladimir-putins-ireland-nuclear-threat-26855413
Nuclear weapons are expensive, not just to build, but to maintain.
The reason the Soviets built only ONE Tsar Bomba is that it cost a megaton (pun intended).
The other reason, and this is important, and something I know from serving six years in ADCOM and 7 years in SAC; is it is not even necessary.
Since the 1960s, both American and Soviet/Russian warheads have gotten smaller as their accuracy and precision of delivery has increased. You need a huge bomb to take out a military target if you’re only accurate to a couple thousand feet, but as accuracy achieves a tighter target, the higher price for a bigger bomb becomes a detriment to building them in large numbers.
In other words, smaller, more accurate missiles is where everyone went in the decades that followed.
They don’t have 100 MT weapons, it’s just braggadocio.
But I do have a serious question for you: Would Russian nuclear weapons even work? They actually require a tremendous amount of periodic (almost constant) maintenance to keep them viable and a lot of money is required to do that. In the meantime, it’s not like they’re being used.
Suppose the officers in charge skimmed off some of those Rubles in order to extend the new Dacha or buy that Mercedes? If they couldn’t even keep the armored tires from going flat, perhaps the nukes will just fizzle on the launch pad.