Russia says it isn't bluffing over threats to use nuclear weapons

Possible scenarios are simplistic and obvious. Predicting future action requires consideration of motivation, willingness to be reckless, spite, religious eschatology that may serve as a driving force, the real possibility of domestic double agents, unknown high level domestic sociopaths, unknown variables, and in our case unknown classified information.

Implied in the discussion is what is being risked given any wrong conclusion. Which, for the sake of this discussion and perhaps in reality, should be assumed to be destruction.

My point is that it is stupid, that is too high risk, to the point of suspicious for powerful people to dismiss Russia's threat as unlikely.

With the caveat that the exception would be if unknowable classified information speaks to Russia being technologically incapable of being successful.

Why? I said that capability is the metric. Followed by threats. Neither absolutely defines response.

The primary takeaway is to NOT believe capable countries who say that they are against using them (China).

When a capable nation makes the threat, only an irresponsible lunatic wouldn't take it seriously. However, a decision can be made from that starting point.

In this instance, the "Russia can't win" take on why they won't engage in such an option isn't good theory in my opinion.

As the invasion of Ukraine was a desperate counter-move. I believe that you are dead wrong in assuming that Russia didn't understand the probable response and outcome until now. I also think that you aren't considering the variable of even other options available to them and China.

But also, that no one can credibly predict a limit to the specific desperation of arguably the most capable nuclear power in the World. Especially in the midst of an active military campaign.