Most of the rest of what you say is at least adjacent to, if not the absolute Truth*, which is better than a lot of commentators. I disagree with the quoted bit, though. The "threat"** was the excuse for some plain, old-fashioned Imperialism. Russia already has borders with NATO members. Who that excuse was aimed at is debatable, but it feeds into the whole "external enemy" narrative the Kremlin has always used to unify their people behind their Kleptocracy. It panders to the prejudices of the polities that feel ill-treated by the First World, and gives the Arch Cynics of China and India "plausible deniability" for their disinterest.
The accession of Finland to NATO hasn't triggered Armageddon, which is suggestive that "Moar NATO" wasn't the problem.
The problem with brinksmanship is that it's difficult to be sure where the brink actually is. Assertions that one thing or another is definitely the thing that will bring about the Apocalypse are largely pointless, which is why the gradualist approach is the only way to escalate. The gradual approach also has the advantage that it can often have the effect of moving the opposition's "red lines" over time. Putin's Russia did that a lot before March '22, to great effect.
* as I see it, at least
** which hasn't been real since at least 1950