I think the nature of war and technology has changed so much since then; if the question is “If WW2 had been fought with technology from 2021, what would it have been like” Then answer is no, they would not have done so because it would have been unnecessary for the same reasons that so far atomic weapons have not been used this century, information and economics are more useful than force. If the question is “Would they have used those weapons if there was a guarantee of greater publicity of the aftermath”. Yes. It was WW2, they were concerned with winning, and in the case of Japan, achieving a fast surrender which would keep the Soviets out of Japan (which was a big concern at the time). Also for the most part, the effects of atomic weapons were not that well understood in the 1940s, so I’m not sure they would have known what that aftermath would be exactly. Its hard to imagine WW2 today, living in a culturally integrated Europe and having been to Japan. Yet it happened, and not that long ago. Humanity has not changed, but I’m still not sure we have the means or the ability to fully understand the thinking of that time in this age of relative peace.