You think you're invincible because of your numbers, well for a culture who supposedly thinks long term, you are kidding yourselves. Japan is re-militarizing right off your coast. Then there is Taiwan that's spending big money on defense.
You may have allies with the Norks and possibly Iran, but do you think with the entire world pissed at you with Covid-19, you will gain any more? You have now become the Soviet Union of this era. Much of the entire world will align against you if you try invade a free country.
You screwed up by not learning the lessons of Hong Kong, and if you don't back off, your leadership will be the targeted losers no matter how deep your bunkers are. You think the US and Allies don't know where they are? If Japan keeps on track with its military buildup, China will go back to dynasty days and forging swords. Don't even think of the few nukes you have.
...allies with the Norks and possibly Iran.
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Aren’t they just vassal states? How does either one actually qualify as an ally?
As you said: China really stands alone.