I often hear the bombing of hiroshima and nagasaki weighed against a full-scale invasion of japan, but this seems like a false dichotomy to me. Was a peace agreement or armstice on the table for the Allies? What made other options more or less viable?
I wrote an article a few years back that is relevant: Were there alternatives to the atomic bombings? It's really an attempt to catalog what scholars have over time identified as the "options on the table" as perceived by the Allies at the time — not so much with a statement that any of them would necessarily be better than the bombings of Hiroshima and Nagasaki, but just to indicate that it was not a choice between just "two atomic bombs on two cities in three days" versus "a bloody full-scale US-led invasion of the Japanese home islands.
In brief, they are:
Vary the schedule: Nagasaki was potentially avoidable if they had just waited a few more days. (This is not a total change to the approach made, but just illustrates that the bombings are not necessarily a singular act, and there were options there.)
Demonstration: Have the first use of the bomb be done in a way that wouldn't have killed many people, as a way to give the Japanese an honest chance to surrender first.
Change the targets: Use the first bomb not on a city, but a military base (not surrounded by a city).
Clarify the Potsdam Declaration: The US knew that the Japanese were hung up on the question of the state of the Emperor in the postwar, and the US could have easily clarified that (and Truman deliberately chose not to, over the advice of many of his advisors, including Churchill).
Wait for the Soviets: The US knew the Soviets were about to declare war on Japan and that this might cause the Japanese to surrender without further mass bloodshed — it would have only required waiting a week or so to see if that did the trick.
You can read the article for the full rationales; my summaries above are not meant to be compelling, just summaries.
I have not explored things that they didn't consider but one could speculate on in retrospect, like just agreeing to end the war on the terms already existing (which was never considered for a variety of reasons). The closest to that would be clarifying the Potsdam Declaration; this would have been done with the knowledge that there was a faction within the Japanese Supreme War Council that was eager to sue for peace, but felt that the position of the Emperor needed to be guaranteed.