FWIW, given everything else that we've seen from Russia in this undeclared(!) war, I'm moderately confident the Russian nukes and delivery mechanisms are sub-par.
(Typing "sub" reminded me of the Kursk nuclear submarine that sank itself…)
It needs only a few to launch successfully to engulf Europe in flames.
So, even with subpar equipment, out of all of the 1700+ launch vehicles a few will still launch.
Some of the P(weapon failure) is constant: from what I hear, a certain fraction of Soviet and US systems (and presumably everyone else's) just don't work.
If that was all it was, then you would be correct.
But: some failures come with age, and require ongoing maintenance to retain function. For example, I expect all the tritium has decayed, and also that in many cases the money that was supposed to get spent replacing the tritium was instead spent on a fancy yacht or a football team or a seat in the UK's House of Lords etc.
And I don't know how good modern anti-missile weapons are, but I would expect them to have improved; conversely, despite Russia's talk about new hypersonic missiles, what they've shown hasn't been very impressive, and they've even used up some of their old nuclear-capable missiles while attacking Ukraine.
I'm happy to be relaxed about this, but only because I have no power — 90% chance some attempted hot war is actually all duds is great for me personally, 10% chance everything burns is unacceptably high for someone running a country.
(Typing "sub" reminded me of the Kursk nuclear submarine that sank itself…)