Any time anyone I know starts fear mongering about China I try to drill this into their heads and they never get it.
America's population is actually not an inverted pyramid. Millennials have similar birthing patterns and sociability to boomers.
Zoomers generally speaking have similar sociability and birthing patterns to Gen X.
For this reason America has a demographic pattern that is like an hour glass. GDP will naturally lower and raise with the hour glass as there is an ebb and flow of buying patterns based on general over socialization vs 'under socialization'.
China (and india, in some ways.) is just boned. China has an inverse pyramid demographic pattern meaning that a majority of the population is closer to death then birth. Not only that but the younger you get, there is actually a worse and worse ratio of Male:Female. As due to one child policy and the disruptive killing of women, there are just less.
Meaning functionally the only way for China to truly even tackle their demographic downturn would be to import (lol).
This is also assuming they haven't been fudging pop stats to stop nations and corporations from know exactly how bad and fast its going.
While I don't believe they are completely lying; it is to be said they have enough people in the nation that realistically no one outside of china is going to get a reasonable estimate. Combine that with their GDP fudging construction projects and all of a sudden you cant really tell how large their nation is, in an economic sense.