To the best of my knowledge Russia retains hundreds of ICBMs and about a thousand warheads ready to fire at a moment's notice. Unless I've missed a crucial bit

To the best of my knowledge Russia retains hundreds of ICBMs and about a thousand warheads ready to fire at a moment's notice. Unless I've missed a crucial bit of news, I'd expect a majority of these to function as intended, as everything I read on that part of their military suggests they're operating a lot better than their army. In that case, an all-out nuclear war would mean hundreds of warheads raining down on the US with on average larger yields than the US ones to make up for less reliable targeting, and even optimistic projections for that and the effects of US retaliation assume three-digit million deaths right away and at least one growing season lost to nuclear winter. All infrastructure close to major population centers, military installations, ... would be gone, as would be anything susceptible to EMP from high-altitude detonations. I don't see Starlink software engineering and the infrastructure they require to remain operational in such a scenario.