This is an argument that has been had for decades, and it’s not going to be settled here. I think this Sean video is one of the best things on the topic I’ve ever read/seen if you have two and a half hours.
I come down on the side that the atomic bomb was unnecessary. Japan was already looking at potential surrender (maybe not the kind of unconstitutional surrender where you let a 22 year old military aide/translator write the constitution over a couple of days…). The decision to drop the bomb was far more motivated by a desire to present a threat to the USSR and to dominate the world stage than it was to end the war.