Japan tried to gobble up China and choked on it.
Germany tried to gobble up Russia and choked on it.
All of Stalin’s trucks and 80% of his ammo was provided by FDR:
If you simply remove the USA’s piggy bank from Stalin’s math, then the USSR either goes away totally or at the very least communism would have been confined East of the Urals.
Japan’s Kwantung army would probably have done fine in China, though in this altnernatve history it’s hard to say when they might have had to face Stalin in the East. But China’s development, like that of Taiwan (long occupied by Japan), probably would have come at a much ealier point.
PRC/Taiwan friction would probably now be a non-issue.