Warning: long post ahead because this is a contentious issue and I had to tap a lot of sources to sketch out this picture.
It is neither revisionist nor propaganda. Yours is the revisionist version, in fact. Not that that's a bad thing. Saying that the civil war was about slavery and not a noble "lost cause" is also revisionist and I wouldn't dispute that. Revisionism gets a bad rap when it's just about revising the commonly accepted historical consensus. For WW2, that consensus for decades was that the bombs ended the war. I wouldn't dispute that their importance was overstated, as I will get into.
That said, the fact that Japanese civilians were being trained in hand combat to resist an invasion is well attested,. as is the massing of suicide small craft to blunt US navy and landing forces, as is what I noted about Saipan. We will never truly know the extent to which the Japanese people would have resisted an invasion, though given the fierce resistance put up by the military everywhere else, it wasn't unreasonable to fear massive casualties in the event. Especially given allied intelligence tracking large scale military build ups in southern Kyushu in the months preceding the bombings. There's a reason we were still using purple hearts made for the pacific war decades after the fact.
I would also dispute that they were willing to have a clean surrender. The only documentation of this refers to Truman's knowledge that the Japanese were making peace overtures to the Soviets, which is true. The foreign office (without the approval of the military) were asking the Soviets to help negotiate a settlement keeping much of their pre-war empire in tact. Even Alperovitz, the arch revisionist from the 60s, claims largely without sources that the Japanese were willing to surrender if they could keep their Emperor and constitution. No new power structure, no war crimes punishments, the same military dictatorship they had been under. I have no problem, if that was true, with the allies rejecting that as unnectable, and it is afar cry from the end result of allowing the emperor as a figure head while otherwise transforming the nations politics and punishing other war criminals. And even that, done in the aftermath of the bombs and soviet invasions, was not actually approved by the cabinet. It took the Emperor's personal intervention to break a tie (with the entire military wing refusing even that), which led to a failed coup attempt against him by military hardliners.
I will agree with you that the Soviet invasion factored heavily into the Japanese surrender, likely moreso than the bombs. But for reasons nobody could have predicted. The fact that the Japanese were holding out for Soviet assistance forcing a favorable negotiated peace - despite historical hostility and the open commitment of the Soviets to join the war - is so outside the realm of reality, that even with the transcripts and cabinet notes as proof, it is still difficult to comprehend. Truman and allied commanders were pressuring the Soviets to enter the war (in an ironic reversal of roles to 2 years prior) to split the burden of fighting the Japanese military and take pressure off an American invasion, not because they had any reason to believe the mere act of invasion itself would suddenly end the war.
Tsuyoshi Hasegawa’s Racing the Enemy: Stalin, Truman, and the Surrender of Japan is an interesting source that takes a third path in the traditional revisionist/traditionalist school. I don't agree with all his premises, particularly that the bomb was more about keeping the soviets out (when we have plenty of documented proof the allies wanted them in, albeit balked at Stalins demands). But while he agrees with you that ultimately it was the Soviet invasion that had a more pivotal role to play in the surrender, the shock of the bombs - and their close timing to the shock of soviet attack - was important in spurring the cabinet, and especially in providing a more palatable excuse for surrender. I cannot find any contemporary sources from Truman suggesting the bomb was about flexing on the Russians. There are diary entries and tenements from aids and journalists accompanying him that he was conflicted about the use of the bomb. You can argue, then, that if he wasn't certain about their value, such a decision should never have been made. You are correct that some high ranking generals argued afterwards that the bomb was not needed to end the war. They also suggested that the japanese were willing to surrender, for which there is absolutely no evidence, and plenty of evidence to the contrary - unless you count reverting to the pre-war status quo as a meaningful surrender. I can hardly blame them of course for thinking so, given how thoroughly hopeless the Japanese position was, a position in which any other country would have long since surrendered.
I can accept an argument (that is echoed in some of those generals you note) that if Japan had been unwilling to surrender in the run up to the bombs, likely nothing short of full invasion would have induced them to. And that dropping the bombs out of a hope - but by no means a certainty or even high probability - that it could prevent the need for invasion, was unjustified. That is going to come down to how you weigh the lives of your soldiers (all casualty projections for a potential invasion was high, and included belief that Japanese civilians would have put up resistance alongside the military. Which is borne out in other incidents) against enemy civilians. I am certainly unsympathetic to the concept of Strategic bombing in general. But it is simply not true that the Japanese were ready to engage in any meaningful surrender, or that Truman and others in the administration did not hold out some hope that the bombs could somehow shock the Japanese into finally giving in, obviating the need for invasion.