You think China has a low tfr. Look at all other east Asian countries that usa is trying to array against the Chinese. South Korea has a tfr of less than 1, i think it is .80.
Even Taiwan has been in below replacement territory for quite some time and they are I think at 1.0. This is with a base population of 23 million at most. They are shrinking very rapidly as a population. China can wait for some time and cultivate some stooges within Taiwan and then strike. Its not like western demographics will improve in that time too. They are likely to get worse and their cultural problems will get to a head.
Also even though China also has below replacement rate birth rates, the quality of their environment and the deliberate cultural choices of the ccp government will help in retaining a population that is atleast sane compared to the defacto woke idiots in the west that are useless for maintaining or fighting for an empire. The GAE - globalist American empire ironically destroys and depromotes the kind of citizen that would prop up their regime. I don't think any of the migrants or illegal immigrants would want to fight for America. They come there for jobs at best and at worst to scrounge for free goods on the dole.
I am sure the Chinese government will have a better quality of people in terms of suitability to prop up empires just by not following and even opposing the weakening effects of wokeism and mass migration.Also Chinese people still have a country to fight for. I don't think the majority recruits who are white and who are relied upon by the elites of the GAE to serve them would fight enthusiastically ever again or even join after their country has been explicitly been tailor made for non whites.
Just for reference, the UK, one of side kick of the US is struggling to man their army of just 65000 to 70000. They are decommissioning ships because they can't man them as recruitment for the navy is also struggling.
The US is also in the same boat and they are not in a critical condition like the UK because they are much larger and have a decent to large budget compared to the UK.
Even if a lot of Chinese men are not fit for combat for various reasons, they will still have 10s of millions of men in reserve and a large army when even 500,000 men is a big or impossible ask for the only based enough nation in europe(ukraine) to produce for their state survival.
That along with the crazy woke secular religion and its policies and its various denominations in the antinatalist, environmentalist,etc movements will destroy any recruitment potential of the types of me they need.
"accidental" 
