Check out “Trinity and Beyond - The Atomic Bomb Movie” It’s an incredible documentary hosted by Shatner. Lots of Atom/H-Bomb footage/info/history and even Russia’s Tzar Bomba 50 megaton blast.
That link has more than a few libridiots spouting the party line on it. Take blood pressure meds before reading.
The movie is on netflix, you have to search for it.