Almost... Another way to see it is they burdened future generations as an expedient measure to save the lives of the people now in the past. Another another way to look at the bomb is preventing another world war.

An interesting historical point is Japan had largely been defeated by the time the bombs were dropped. And they had the option to bomb an uninhabited (or very lightly) part of Japan's territory as a show of force. But, instead they specifically chose to irradiate civilians.

It is also interesting that the movie focuses on the scientists developing the bomb over everything else. There is a removal of the protagonists from seeing the destruction of their work, but that was done on purpose by the military. Even within that, you see a discussion of morality of the bomb by its developers and that the scientists, in almost all cases, have a more nuanced understanding of the destructive power they are developing and the ethics of using such a device.

This is of course just my opinion, but no horrors, imaginable or otherwise, that the Japanese could've possibly orchestrated at the time, with the means they had available, would've come close to the devastation caused by the bombs in Hiroshima and Nagasaki.

Is there a Japanese film like Oppenheimer but from their perspective? I've seen plenty of stuff that feels influenced by Hiroshima and Nagasaki, including the horrors from a perspective unique to people who have first hand experience; but it's all fictional.

Like, is there maybe a movie about the dude who survived both bombs?

Also that the alternative was burning cities with the people still in them, and they'd seen that, which was have been more horrifying and slow than a nuclear conflagration.