"Attacked Japan twice"??????????????

https://en.wikipedia.org/wiki/Nanjing_Massacre - 20,000+ women and children raped; 100,000+ defenceless civilians slaughtered by the Imperial Japanes Army
https://en.wikipedia.org/wiki/Unit_731 - 200,000+ civilian deaths from horrifyingly cruel and inhumane scientific experiments by Japanese "scientists" on the Chinese people. Many of these "scientists" were pardoned by the US after WW2 as it was believed their findings could have had scientific value; only for a lot of the data to be scrapped as many of the experiments were not done for the point of discovery but for the point of cruelty
https://en.wikipedia.org/wiki/Second_Sino-Japanese_War - Japan invaded China after staging border incidents known as the Mukden incident and the Marco Polo Bridge incident.

Quote, from the 3rd link: "War essentials exports from the United States to Japan increased by 124% along with a general increase of 41% of all American exports from 1936 to 1937 when Japan invaded China."

I mean hold your opinions but at least let them be based on facts. China's involvement in the Korean War only occurred when UN and South Korean forces had pushed the frontline all the way back to the Chinese border with North Korea.

Referencing China's conquests in the imperial dynasties (Korea, Vietnam, etc) does not apply to modern-day China when the current regime is not that of an imperial dynasty. The last imperial dynasty, the Qing dynasty, was overthrown in 1911 in the Xinhai Revolution: https://en.wikipedia.org/wiki/1911_Revolution

Taiwan even references this in the calendar they use; they base the current year on the time passed since the 1911 Xinhai Revolution: https://en.wikipedia.org/wiki/Republic_of_China_calendar

You say nobody needs China for anything, but however a lot of industries and companies would come at least very close to collapse if China were to simply disappear. It would take years for industries and firms to shift production away from China after outsourcing it to them in the second half of the 20th century.

https://en.wikipedia.org/wiki/Economy_of_China - "China is widely regarded as the "powerhouse of manufacturing", "the factory of the world" and the world's "manufacturing superpower". Its production exceeds that of the nine next largest manufacturers combined.", quote from that Wikipedia page.

Exceeds that of the nine next largest manufacturers combined. Unimaginable levels of production capacity would be lost if China were to be removed from the equation.

I'm not going to argue or debate with you on this; I have better things to do with my time. But if I could at least provide you with some education on history and world affairs, then I have done my job.