You wanna go back to history? Why don't we go to back to the Cold War, where China sided with the US against the Soviet Union and led to its collapse soon later?
Why was it called 'Cold'? Because there were no real shooting between the superpowers. Not talking about proxies like Viet Nam, Korea, or the Latin America countries.
We are talking about WW II where diplomacy took second seat to military, that is why Clausewitz said war is 'continuation of politics by other means'. Politics are inevitable when there are different desires. Politics exists between friends, husbands and wives, siblings, and in the workplace. War is when the diplomacy part of politics failed to resolve those differences.
Now that is out of the way...
WW II was a shooting war, not merely a 'war' of words. As such, the only way you can win a shooting war is when you are able to put
PHYSICAL pressure on the enemy's abilities to wage war. Words do not work. Remember, words already failed and that led to a shooting war.
China did not contribute to the defeat of Imperial JPN. Yes, China fought JPNese troops, but that was on mainland China and against an army that was entrenched on Chinese soil for yrs. China was fighting a war of repulsion: to expel someone. That last thing China focused on was on how to put any kind of
PHYSICAL pressure on JPN or any of JPN's overseas holdings. No Chinese military assets fell on JPN regarding that
PHYSICAL pressure necessary to defeat an enemy. The Kwantung Army was defeated by the Soviet Army. Sure, you can argue that China's own forces contributed to the weakening of the Kwantung Army that enabled the Soviet Army to executed the
coup de grace, but between China and the Soviet Union, only the Soviet would be able to land troops on JPN.
It was US bombs that fell on JPN, going all the way back to Doolittle's raid on April 1942. It was US naval engagements that drained JPN's national resources. Ships requires support, land forces less so and the Kwantung Army received next to nothing from JPN. Back then, China could not cross the East China Sea to land on JPN, but the US could, and the JPNese military leadership knew it. JPNese ships lost at sea meant more pressure on JPN than JPNese troops lost on mainland China.
Ultimately, it was US nuclear weapons that exerted the final physical pressure on Imperial JPN to surrender, not what Chinese forces on mainland China did to JPNese troops.
You guys, and your supporters on this forum, do not understand these military issues simply because none of you ever served. Am not saying that to be mean but to point out reality.