With 30% of its total energy consumption coming from electricity (vs about 18% for the rest of the world) and electrifying "nine times faster than the rest of the world", China is becoming the world's "first major electrostate".
Source: https://rmi.org/insight/x-change-the-race-to-the-top/
This is true and is almost never mentioned. Much of "China's pollution" is actually the West's outsourced pollution.
China has a population of 1.4 billion, that's quite a long way away from 2 billion. Still, your point remains valid. China has double the population of the US and EU combined but around the same CO2 output as US+EU.
Unfortunately this is not the case. China remains the country with the largest carbon footprint in absolute terms, though it also has one of the fastest growing green energy sectors, is the largest producer of solar panels by far, and is electrifying at a crazy pace.
Another thing that is frequently overlooked or purposely omitted are historically cumulative emissions, and in this case China doesn't even come close to the total CO2 output of the US from 1900 to today. And it only takes maybe three or four major European countries combined to overtake China in this regard.