i don't trust anything the russians show off...their tech is behind ours significantly in almost every aspect, and several of their "super weapons" are not super at all...their hypersonic missile is a pile of shit, i doubt if 99% of their left over outdated icbms will even take off if loaded up, and their subs are a generation behind ours, at least...
if it comes to it, russia might get one round of missiles off, 95% + of which would be shot down. the 5% that gets through would be problematic...and then either we would retaliate, and russia has fuck all to shoot down our missiles, or NATO would invade full force and TAKE every nuke the russians have. every sub they own is tracked closely, although it is conceivable one could evade detection...one sub worth of nukes off the American coast would be bad, but not as bad as a nuclear escalation would be for russia, the only reason putin hasn't already used a nuke is that he knows that would be the death of russia, permanently.