The firebombing campaign against Japan in 1945 was very effective. Millions of people injured and homeless put a serious drain on their war effort. Thousands of industrial establishments were destroyed which cut production to a level below subsistence. And the bombing also weakened civilian morale.
The same could have been done to China. If 300 B-29’s dropped 1,000 tons of incendiary bombs on Beijing and burned the city to the ground, then the Chinese would realize that they should pull out of the war.