See, the problem with this is that he never did threaten that. It's CIA propaganda. Indeed such a threat would make zero sense even logically, since from the standpoint of China (and the US State Department) Taiwan _is_ China.
Xi Jinping opened the Chinese Communist Party's twice-a-decade National Congress on Sunday by pledging to never renounce using force to take control of Taiwan
https://www.aljazeera.com/news/2024/4/10/chinas-xi-says-outs...
Chinese President Xi Jinping has met former Taiwanese President Ma Ying-jeou and said that outside influence cannot stop the “family” reunion between Beijing and Taipei....Beijing views the self-ruled island as a province that must be reunited with mainland China, and it has not ruled out using force to assert its claims to Taiwan.
https://www.reuters.com/world/asia-pacific/china-calls-taiwa...
China's "reunification" with Taiwan is inevitable, President Xi Jinping said in his New Year's address on Sunday, striking a stronger tone than he did last year
https://www.nbcnews.com/news/china/xi-warned-biden-summit-be...
Chinese President Xi Jinping bluntly told President Joe Biden during their recent summit in San Francisco that Beijing will reunify Taiwan with mainland China but that the timing has not yet been decided
The US has also never engaged with the Houthis, except to protect marine shipping. There was never an attempt to "defeat" them by the US.
North Korea has an ongoing war with South Korea for the last half a century. There's a mutual defense treaty between South Korea and US to provide mutual aid if either faces external armed attack. North Korea also has a mutual defense treaty with China. Thus US need bases around South Korea.