Russia may threaten and posture the use of nuclear weapons, and have started a losing war with their neighbor, but it’s far less likely that they would actually use the weapons. Even if Putin ordered it there’s a lot of people between him and the weapons that could prevent the use. He’s a dictator but barely, he needs to keep the oligarchs happy to keep his office, and the oligarchs don’t want to live out the rest of their lives in cramped bunkers in Siberia when the earth is irradiated. DPRK on the other hand is an actual dictatorship, with few people between Kim and a launch, and is actually unstable enough to do it. Also, with their carelessness around their “test launches” they’re much more likely to cause an international incident by dropping a half-fueled rocket stage on Japan.