Should I repeat: half of the Chinese in occupied/annexed territories are in fact allied to the Euros/Japs, and actually ruled by their own warlords/factions.What next? The Boxers on steroids. (The pun wasn't intended but it works nicely).
And what actually stopped the combined might of British, French, Russian, German, and Japanese armies from crushing those "Boxers on the Steroids"?
Similar with India: far, far larger wealth and population than Britain, yet the Raj was able to...well, yeah...Over 1/3 of the wealth of the world was centered in China just a few decades before the POD and more people will live in China (over 300 Million) than in Europe, more than twice that number.
If one power could hold onto India, why several powers couldn't hold onto China?