PR China is still pretty poor (around 31k$ gdp per capita adjusted for purchasing power) and its growth has lost a bit of steam recently.
You should wish your country to be more like Taiwan or South Korea. Or Singapore.
My country is currently at about a third of that.
Total fertility rate for all of those countries is close to 1.0, including China's. They are dying societies.
You might want to compare Singapore with a city like NYC or London, not with a territorial state. It's pretty normal around the world for cities to be replenished mainly by people moving in.
(Of course, to be fair you then also need to compare GDP per capita against other cities. And they usually do a lot better than territorial countries that include a lot of hinterland.)
Singapore was and is build on the back of immigrants. Replacing ourselves with kids instead of immigrants would be the big change.
No this is a non-sequitur.
Low fertility only means that the affected society grows smaller. This is only equivalent to "slow death" when it persists for centuries until the society is actually dead.