The Japanese populace, whether they wanted to or not, was fully prepared and planning to defend the home islands with their lives as gruesomely as possible.
If America had not dropped the bombs and the Soviets ended up finishing off Japan like so many seem to think they would, the Soviets at the end of the war were NOT known for being gentle in their dominance.
There was no ending to Japan in WWII that did not kill hundreds of thousands of civilians.
Strategic bombing were attempted multiple time during the war (first by the Germans on UK, and the UK/US on Germany then Japan) without success (and in most cases it actually strengthened the resolve)
That’s the horrifying thing, killing hundreds of thousands of civilians so your enemy surrenders.