Scott Ritter is former marine, UN weapons inspector, and convicted pedophile. Ignored by anyone who has any knowledge of international affairs, he has become an imbittered anti-American tool of the Kremlin. He is beloved by some of the far right conspiracy loons in this country. He is a regular guest of the Russian propaganda "news" programs where he condemns the US government and particularly US support for Ukraine while praising the Russian government and Russian culture. His last book was published in Russia and he conducted a book tour in Russia.
Russia is not going to start WWIII. Whether or not there would be a winner, Putin and the mafia that controls the country and its armed forces fully realize Russia would be the absolute loser. Russia spends very little compared to the US on maintenance of its nuclear forces. Plutonium devices require constant tuning and refurbishment to operate as designed. Russia's may all work perfectly, but then again a large percentage may not.
Russia's SLBM capable submarine force is under constant surveillance. Particularly since Finland and Sweden joined NATO, a Russian submarine can't flush a toilet without being observed. I have a high level of confidence that Virginia class boats would provide a warm greeting to any that entered a firing sequence.
What Russia can count on is that US nuclear TRIAD will work as designed, the weapons will strike within feet of their intended target, that the Russian armed forces have no way to stop them, and that Russia as state and culture will vanish from the face of the earth.