China invested a lot in biotechnology and has few ethical concerns in this regard. This scenario might be within the realm of possibility for them.
The word for that is "invention" and I believe I used it in correct meaning (not a native speaker of English). There is nothing unthinkable about artificial wombs, though it is obviously hard. The research runs in Western countries as well. If Western scientists thought it was principially impossible to construct such devices ever, they wouldn't probably spend their time and grant money on fiddling around that concept.
Now China has a) a lot of classified research, b) fewer ethical concerns, c) is aware about their future demographic problems stemming from One Child Policy. I would be surprised if they did not at least try this approach.
As for curing aging, the longevity field seems to be more developed in the West so far, even though their aims are more modest - prolonging the healthspan by, say, 8-10 years. While not a solution, such progress would definitely buy some time.
Interestingly, there is a very niche subset of longevity research that looks into reproductive health of women over 40. It is possible, though far from certain, that oocyte quality could be improved even in older women - where aneuploidy is otherwise a big problem.
A lot of bizarre fantasies about what the Chinese government can and can't do - they are an authoritarian state, not a totalitarian state. The idea that they can enforce multiple births in a culture that is trending sharply away from having multiple kids by waving a wand is just ridiculous. Further, they have barely deployed any serious incentives to have more kids - it would be cheaper and easier to do Scando-style childcare and subsidies.
The other basic fact that your responders ignore is that Western countries have huge immigration rates compared to China, which hardly has any immigration. Their rate is 750 times lower than the USA, for example, and the bulk of immigrants to China (historically) have been from ethnic Chinese populations abroad (notably Vietnam); these populations are also aging.