I don't see it.
I have been wandering astray in my mind speculating to myself on just how far back and deep a POD is needed to take the US out of the picture completely, or so nerf it it cannot just spam Japan into total defeat.
Aside from such speculations which I suppose need PODs in the 1880s if not earlier, perhaps as late as the 1890s maybe, we have an aggressive and very self-righteous USA and almost inevitably a deeply racist one too. A lot of domestic influences might stay the hand of imperialism for the hell of it, but if we grant a situation like late 1941, and something closely akin to the OTL near-simultaneous strike at both Hawaii and the Philippines (they were meant to be actually simultaneous, but bad flying weather delayed the strike out of Taiwan on the Philippines) then I don't see what would stop the Americans from intending to grind the Japanese empire down to nothing as OTL, however long it took.
Supposing for instance that one reason it takes longer than Spring 1945 to bring the Reich to heel and total surrender is that the Soviet forces falter badly giving the Reich a reprieve and a longer grip on Eastern Europe, and perhaps even pushing back east for a while.
But OTL it only took a fraction of total Soviet force tied down near the Pacific to deter even the Japanese militarists from biting off yet more to chew north of Manchukuo. If that fraction has to be withdrawn westward to stop a Reich resurgence (which seems nigh impossible to me given that the same sort of economic shortfalls due to lack of crucial resources worked against the Reich as much as Japan) maybe the IJA can move north into the vacuum?
But even granting they can secure all the resources the Soviet far east offers, and have the time to repair damages to established formerly Soviet infrastructure and start expanding, that's thin gruel gleaned out of tough terrain; even if they don't have to worry about the Soviets themselves coming back any time soon they still have to garrison it and then someone or other has to labor to extract the resources.
So now the Allies cannot threaten the continental based IJA forces with a Soviet steamroller.
But such a USSR on the ropes is hardly a threat to post-war Western allied and in particular Yankee hegemony; sentiments anything like OTL ones would favor poor beset upon Ivan and keep aid flowing to them, while the sad reduction in Soviet ability to win the war for us in Europe would compensate greater Western loss of life with surefire Western-ally rule over the former Reich conquests eventually.
No reason then to cut losses in East Asia, whereas we have I think already left the OP suggestion of better IJN/IJA holdings in the sweep of the Pacific far behind. The Allies OTL, with the US forces doing a lot of the heavy lifting, won supremacy over the Pacific pretty handily by the end of 1944 with their hands almost literally tied behind their backs. The Reich forces winning some kind of Pyrrhic victory on the Eastern front only to be dismantled from the West would surely result in mass numbers of American along with Commonwealth as well as exile forces being tied down to occupy the OTL Soviet Zone along with their OTL western holdings--but they would be assisted by various native allies with their own scores to settle with the Axis and its collaborators outside of Germany (including of course Austria) itself.
For that matter unless we postulate the complete meltdown of the Soviet system even far back from the front, I imagine the western powers would hand everything the USSR held in September 1939 right back to a restored Kremlin government in liberated Moscow, and that after the experience of Axis rule such a government would find, if not universal acceptance, the support of enough once and future Soviet citizens among the survivors to keep some sort of order. And enjoy some considerable largesse of aid to start recovering. If the Japanese have in the mean time made incursions into pre-war Soviet territory, this would just motivate the decimated but still in being Soviet state to provide at least token force to hold the line against yet more Japanese expansion there again reinforced by some diversion of western power.
So meanwhile just as OTL, the Japanese might continue to have forces occupying islands far out into the Pacific, but these as OTL would be isolated, essentially self-sustaining prison camps, with Allied, mainly USN, warships and either civil or formally military transports cruising around knitting the directly conquered territories into an economic whole, largely under self-rule, permitting considerable seasoned US and ANZAC along with British and now French and other liberated nation troops (Netherlands, Scandinavian, maybe the Swedes would at this point join the UN alliance too even Italian forces, possibly fair numbers of Yugoslavs and Czechs) to concentrate on the next objective.
Tied down and decimated versus OTL, the Allies might want to hold off on simply invading the Home Islands, but instead mop up south to north, liberating Malaya, coordinating uprisings and extirpations of Japanese power in Indonesia and recruiting Indonesian expeditionary forces in a deal that absolves and forgets the collaboration of some Indonesians with the Japanese, similarly invading and regime-changing Thailand presumably keeping their Emperor with a different cabinet, working with the Indochinese resistance and cutting some kind of deal Ho Chi Minh or perhaps some rival nationalist outfit can live with for Vietnam, then north into southern China to link up with and absorb Nationalist forces that for the moment anyway are somewhat enhanced with Chinese Communist allies and, with Chinese troops providing the numbers while mostly US with some Commonwealth help provides the munitions and other supplies, start slugging it out with the Japanese forces based in China. The farther north they advance, particularly on the coast, the more vulnerable both Japan itself and all the oceanic channels of communication with it are to the tightening noose.
You can say the IJN Fleet In Being is avoiding battles they cannot win, but my point is, there really aren't any battles they can win; either they keep retreating or any stand they make, be it a tactical holding action to cover more retreat or a last apocalyptic battle, is defeat, incrementally or wholesale. At some point they will be weak enough even if they have previously occupied the entire formerly Soviet Pacific coast to be dislodged by landings in say the far south of Sakhalin and that island stretching between Hokkaido and the mainland, and effective logistic contact with Korea must soon be interdicted leaving the Japanese archipelago entirely on its own, and subject to withering attack.
Nothing OTL suggests that even if the USSR were (improbably!) to suffer some kind of stroke, that the USA at any rate would run out of manpower or will to keep slogging on, particularly as the longer ultimate victory is delayed, the more time there is to get reconstruction of liberated territory under way and recruit at least token forces from the liberated zones. Gradually the attrition of American GIs and Commonwealth Tommies slows down as liberated zone recruits take more of the decreasing number of bullets and mines the Japanese die-hards can inflict, relationships between these regional local allies and the Western power forces build up, and meanwhile the USA in particular has slack versus OTL for yet more intensive wartime production with ever more advanced equipment.
Meanwhile another clock ticking away is the Manhattan Project. I'd object to ATL suggestions of A-bombs being made available a lot earlier, and also to suggestions that they could be churned out in large numbers very quickly--the bottleneck was production of fissionable material combined with relatively inefficient early bomb designs requiring far larger amounts of that stuff than bombs of say 1948 vintage would require, meaning also heavy airplanes (Silverplate B-29s, no other design was really up to it OTL, some British bombers had heavier warload capacity but could not climb nearly as high or fly as fast) to deliver them. BTW if the IJN is anything left to reckon with by summer 1945, devising fission bomb torpedoes seems pretty straightforward to me--might require a B-29 Silverplate analogy special sub design to fire one supersized torpedo, but that would be all it takes to take out a capital ship completely even if it misses a direct hit, by hundreds of meters!
And turning back to the European theater, if some ATL event delays OTL V-E day such as the Red Army faltering--well that just buys time for the OTL Hiroshima bomb to be sent to blow up Berlin instead, or maybe some target farther west that would really weaken German defenses. Versus OTL, if the war is still hot in Europe come August 1945, Truman (I think given how conservative you are being about ATL stuff, we can assume it is he by that point) might decide to delay the first A-bombing of enemy forces until the US has a fair number of articles in hand, say 6 or more, which even with accelerated priority to the plutonium generation pipeline might take a good long time, say until winter. By that same token though, if there is some rump Reich in being in January '46 still to threaten, Japan will have meanwhile been attritted more than OTL and the Bomb finally being used might give them the excuse they needed OTL to finally throw in the towel.
The Allies don't even need to carry out Olympic in any version is what I am saying, unless you arbitrarily on top of a POD of different mentality in Japan also throw in nerfing the MP to be slower or more misguided than it was OTL. I would object to accelerating it, but also to slowing it down much too; it was a matter of plodding along generating droplet after droplet of fluids containing fissionable U-235 or plutonium day by day. They had at least a half-assed but workable design (two of them in fact, one, the Little Boy uranium gun-type job being even more inefficient, but still effective, overall lighter if considerably less powerful) in hand and proven at Trinity (Little Boy was considered so simple and sure fire it didn't need a demonstration test) and making six or seven more would just be a matter of doing the craft work after accumulating the material.
We can delay the defeat of the Axis, if you can come up with something reasonably plausible to spoke the Allied wheel pretty good, into 1946 perhaps then. Not longer! Eventually Uncle Sam is going to have A-bombs, and against foes with crumbling infrastructure and lots of occupied victims with scores to settle and the general writing on the wall of their eventual doom writ so very large, we don't need dozens of them to knock them out.
Going toe to toe with Ivan in the later '40s is another matter, one thing the Russians have is defensive strategic depth, another is sheer mass.
But if the mechanism of delaying the war end is nerfing the Red Army somehow, well the burden is on you to do that plausibly, and maybe then if we make a good case then the Soviets are also vulnerable to express nuclear decapitation with the sorts of bombs perhaps...but in such a case I think the Reds would be so dependent on Western aid they would be compliant--especially because enough pro-Left sentiment would exist in the major Western powers and enough democracy would be in force that intolerable demands would not be made to abolish Bolshevik socialism completely, just to try to institute some sort of due process and meaningfully democratic oversight over Party rule, which on paper is perfectly compatible with Leninist ideology, as repugnant as it was to the Party bosses in practice. Under these circumstances, a restored USSR with pre-war borders might not appear to a threat at all, and its surviving leadership might not feel threatened either, and liberated territory would be under a truly collegial UN regime fostering actually democratic successor states everywhere. So yeah, Uncle Sam might be able to unilaterally break such a weak Soviet state--but lack any motive to plan to do any such thing, nor would any other standing power justify a massive A-bomb arsenal either. We'd probably balk at putting all authority over all nuclear tech under a real world government and insist on monopolizing it ourselves, but that position would be undermined by the ability of at least the British, and probably the French soon enough, to independently develop their own capability and we might at least agree to allow UN inspectors the ability to monitor and check our unilateral ability to deploy the things.
Anyway this thread is not supposed to be a vehicle for a liberal-pinko Utopian postwar order, its OP premise strikes me as quite the opposite, trying to justify the persistence of a quite authoritarian regime with a dangerous tendency to militarism, whereas I suppose I sound quite contradictory of myself having freely labeled my own country as racist and imperialistic before.
I think I can reconcile it somewhat though by saying the bottom line is, we can't salvage Imperial Japan once it goes militaristic without some very dramatic shifts in the overall balance of interwar power that makes for a completely different world that probably requires a pre-Great War POD, even if only to justify a different Great War outcome.
After 1920 or so the major hope to spare Japan a whole lot of pain is to somehow divert the Empire from its OTL fall into militarism, which is a tall order given the ruthlessness of the Great Powers and the ruthlessness of Japanese nationalism. For a nicer result someone has to be nicer. And the Japanese were not in a great position to be magnanimous.
To be sure, their behavior in Taiwan was not nearly as nasty as it was later in Korea and Manchuria and their post-Pearl Harbor deeds, so that's where I'd go to put Imperial Japan on a different course--to somehow persuade the Japanese culture to develop on more inclusive and tolerant lines that make for the Koreans and eventual other subjected peoples more participants in a cosmopolitan Asian system.
And that if accomplished might tragically still not save Japan from her fate; European and American onlookers might see it as just as threatening and indeed worse for its subversive effect it might have on their own imperial subjects in Asia and perhaps globally.
Such a development might however put the ATL "Greater East Asia Co-Prosperity Sphere For Real" into a stronger position to resist conquest and negotiate for reasonable terms of co-existence with the established imperial powers, particularly if on one hand it gets going early enough to be tough to dislodge and on the other wins moral support among democratic constituencies in the liberal Great Powers.
I say nations like my own USA are racist and imperialist and certainly evidence supports the claim we often act that way, when push comes to shove. But I am also serious about democracy, in general for everyone and in particular for the more positive aspects of the American federal republican experiment, and I do always hope decency can have enough force to enable frustrated greed to be reconciled to alternative paths of mutual benefit I do believe always do exist in principle, if only people can be decent enough to give it a chance. The ugliest aspects of human behavior can be at least diverted, I think we have plenty of evidence of that too, so I'd rather think in terms of more of that rather than less.
But give me the world as it was OTL 1920, and sadly while Japan had not solidified into its militaristic course yet, it seems pretty much doomed to fall into that eventually and for the only humane resolution of it to be total defeat much on OTL lines. I can imagine other paths, such as perhaps internal revolution, arriving at a somewhat similar ending of that particular nightmare, but none that aren't traumatic and none that guarantee a very happy ending for anyone.
It could be even worse than OTL, and frankly I see your OP, even if we saw a straight path to it somehow, would be worse. Either a regime that normalized very brutal behavior and upheld seriously twisted values it is unlikely to find any internal path to reform prospers on those terms unchanged...or a catastrophic check on it bringing the whole mess down in ruins comes later and in all probability worse with even greater pain.
