An overblown story

There is no evidence that US would supply heavy bombers to Chinese for long range bombing. China had neither the facilities to support a massive sustained bombing campaign nor escort fighters with sufficient range. What China lacked was not a few planes (or a few guns), but an industrial base to sustain a modern war.

It was only very late in WWII that US Army Air Corp. deployed bombers for targets in Manchuria, and in Kyushu, by then the Japanese had lost most of its experienced pilots and airplanes.

Ironically, China did received a number of heavy bombers (the Liberators-B-24)and had pilots trained by the US, rather late into the war. I am not aware any combat missions of these planes flown by KMT pilots against Japanese, but they surely were in action in the civil war that followed.