Thanks! Still watching it, but I gotta say this YouTuber plays it rather fast and loose. One of his first points (that finally comes after a good 20min of pushing his own ego and going through the 'offial' story) is that a small yield 'nucular' explosion would have been detected. Fusion explosions can go down to kilojoule range, fission - undergoing explosive chain reaction accidentally - may be in tens of tons of TNT range. There's some recent paper that describes the first smaller explosion of Chernobyl as such a small yield nuclear explosion.

When someone just claims (s) he is thorough I immediately get suspicious.

That being said, the central thesis might hold up and I still have to watch the rest.