I doubt this.
Frankly had the Soviets escalated, that is precisely what the Manchurian Commanders wanted, that would have had the Japanese General HQ in Tokyo have to support their conflict, and as such the Imperial Japanese Army and Air Force in China would have been given free capacity to act, and mobilise.
Meanwhile in Japan the General Government would have to call a state of emergency and mobilisation, as fitting to the conflict.
In principle, the Japanese could have at least a million men in Manchuria by the next summers offensive. If they do or not, is a separate question. It is far more likely that there would be a stalemate along southern Manchuria.
However let's get back to the OP and watch the butterflies...
...where Hitler is removed and WWII is fought between the Allied Nations of Europe and the USSR....the political situation. ... realistic POD's with Hitler simply dying in the trenches ... Federal German Republic and an aggressively expansionistic USSR.
Set up as an Alternate History Challenge;
Hitler dying in the trenches, very plausible. The gas attack that put him in hospital our timeline kills him in this timeline.
Federal German Republic, very plausible, it is likely that without the Nazi's the Weimar Republic may have survived and gone from strength to strength.
Allied nations of Europe, highly improbably, unless there is a significant other threat, even the Soviet Union might prove tricky on this score. Following the Great War, the Nations or Europe don't want more war, the policy of appeasement, the building of the Maignot line etc. the political feeling is to avoid that.
Germany's Army also went back to Germany 'victorious', even though Germany surrendered, there is a wound to lick there, since many people felt 'let down' by the home government. However over time this sentiment may fade a little.
The Entente of Britain and France will likely hold, however over the 1920s will still come to generate animosity with Italy and Mussolini, as well as Russia, as the Russian Civil War turns to radical communism. In Asia, the American depression during the 1930s will still likely affect a rise of militarism in Imperial Japan, to cause the Invasion of Manchuria.
In the early 1930s, a lack of a 'strong leader' in Germany, likely causes a slowing of growth within Germany, and a greater movement towards left-wing radicalism, although the more prevalent Conservative movements may be able to keep a lid on the political situation.
The Soviet Union becomes somewhat more isolated from the global community, but is also considered with a lot more sympathy by Eastern Europe due to grass roots left-wing politics.
By the mid 1930s, without Germany under Hitler, the Japanese are less than sure about the omens of a war in Europe, there is general more stability in the world, and no major antagonist in Europe to distract the western powers. This leads to the militarists position being somewhat undermined when they find it harder to force civil opinions in the diet.
By 1936, the attempted coup in Japan likely goes the other way, with the militarists being framed as being 'warmongers' and all militarist factions get a rebuked via the Emperor at reminded them who they serve. This attitude may ferment a form of warlordism within the Imperial Armed forces.
By 1938 the Weimar Republic is back into growth, although Versailles is still fairly crippling. However Mussolini and Fascism is a growing threat. When the Spanish Civil War Erupts Italy backs the Nationalists, however in this timeline the greater support from the Soviets and rest of Europe swings the conflict in favour of the Republicans, much to Mussolini’s displeasure, hence he concentrates more on fermenting fascist principles in Yugoslavia to secede Croatia as a state. Unrest in Yugoslavia is waited out.
With Stalin at the helm of Russia, but little major threat more effort is geared at internal crackdowns, industrialisation and securing his seat of power. Support in Spain might cause him to try and ferment similar support in Iran, eastern Turkey, Poland and the Baltic States. This occurs with limited success.
In Asia the rebuke from the Emperor causes the various factions of the armed forces to consider a more extreme measure. The replacement of the Emperor with a new Shogun.
I might suggest a relative period of anarchy within Imperial Japan during this time, with coup, and counter coup, and successful and failed schemes. This effectively paralyses Japan for a year or two due to open internal factional warfare, during which the Emperor is assassinated, only to be later replaced by a puppet from the victorious end faction. Circa 1940.
Mussolini, meanwhile has made Italy become geopolitically isolated, and there is some movement to remove him from power, however the popular support and urgency of his own position leads to Italy mobilising and supporting a Croat coup to secede territory in Yugoslavia, and allied states.
Internationally this is condemned, and both England, France and Germany may try and order through the LoN for Italy to remove its troops from Croatia, and return territory to Yugoslavia proper. However the LoN is too slow compared to the situation on the ground that has itself erupted into a form of internal civil war and within a few months, Italy has seceded a large portion of northern Yugoslavia, and parts of the Adriatic coast. France and Austria mobilise, but in general nobody wants to start a conflict, and instead Italy gets embargoed and looses international face.
Within a few months the situation in Yugoslavia resolves itself with pressure from other nations like the US and Soviet Union to stop the conflict and restore peace.
Yugoslavia thus gets split into Croatia and Serbia again, with Italy also forcefully having annexed Albania into its Empire. British-Greek relations gain a major boost as Britain moves to support Greece's independence in the region. The Soviet Union, also takes it's move to do the same with Bulgaria, and Romania.
While somewhat successful, the internal politics of Italy might throw Mussolini out of power, since surrounded and with no friends its not doing Italy much good.
In China, the Nationalists finally overcome the Communists.
As the new 'Shogun Japan' reforms itself it might take the view to annexing Manchuria proper, as well as installing regional governments across Manchuria, Korea and Japan installing a form of 'neo-fedudal' system. Where the military itself controls the civilian government.
Britain and the US might object strongly, particularly as the new Japan likely ignores all treaties previously signed to expand its fleet and armed forces, much the same way as in our time line. Yet far from actually going to war, internal strife leads to much sabre rattling instead.
The Soviets? Stalin has more crack downs, while considered moving many more forces east.
By mid 1940 Britain is having problems with India, and its moves for independence, as the world is less distracted via war, it gets more publicity, and the question becomes a major issue, eventually being decided that a long term plan for India to gain its independence shall be enacted.
This weakening causes Stalin to up efforts in Iran and the Middle East, however Poland and the Baltic’s are still asserting themselves to resist the Union. Tensions grow. Left-wing movements in Poland and Romania grow.
Britain and France decide they need to exert influence to protect eastern Europe, reluctantly having to gain German support for this, the major opposition being French.
Stalin 'laughs it off' to some degree, and instead spins it as propaganda to Imperialistic powers exerting their authority.
Over the next 5 years tensions and military build-ups continue, when left-win rally s in Poland/Romania are put down, it becomes the powder keg for war.
Japan, sensing an opportunity makes its moves in the east...
Hence;
Red Alert 4 sans chronosphere