Does it ever occur to ask the people in Taiwan, which is a democracy, what they think?
Wouldn’t stabbing a democratic ally in the back be a precedent for stabbing Israel in the back?
China has already made it clear that if North Korea starts a war, they are on their own. Trump can freely nuke them (since under international law, one is allowed to nuke countries that have nukes), and let the South Koreans clean up the mess. If the US also offers to withdraw troops from that region (where they aren’t all that popular, and where it is expensive to station troops since these are all industrialized countries), the Chinese will be delighted.