Increasing birth will never work in cities and metropolitans. Having children means it's necessary to have bigger house and housing's price in tier-1 and tier-2 cities are just ridiculous. Rural areas is where you should encourage birth. In countryside in China, you basically can have a house for free and rural China is not yet so immersed with Western culture and modern lifestyle.
Institute property taxes.
Develop the country side / tier 3+ cities.
Encourage people to work remotely / migrate to the country side and build houses there.
Use the proceeds from property taxes to give tax credits to people for having children.
Start a fertility media campaign; ban all voices to the contrary (especially Western consumerist brain washing).
A culture war against the "death cultures" of South Korea, Japan, and the West needs to be declared. Demographics is probably the greatest strategic and national security challenge facing China today. If it doesn't take it seriously, then it
will lose the global contest vs. the West because old people
cannot win vs. young people
.