Oh, I've written several. If only people here actually bothered to read rather than just grandstand on their soapboxes...
In any case, I'll summarize my beliefs about this issue. There are broadly two major disincentive structures that the government should tackle - one is economic and the other cultural. The economic one has begun to be addressed with the "common prosperity" platform and the deflation of the housing bubble. That's an excellent first step, but a lot more will be needed. Broadly speaking, I think the government should implement a program of "affirmative action for the two child family." Essentially, various ways of transferring wealth and opportunities to the preferred group at the expense of not-preferred groups.
The cultural one is more complex and difficult to measure, but I think that the Chinese government should exploit its unique level of influence over Chinese society to suppress anti-natal trends in popular culture, traditional media, social media, etc. and boost pro-natal ones. For example, instead of flaunting wealth, it would be much better for celebrities (and much better for their relationship with the government) to flaunt their kids. Over time, the cultural shift will percolate throughout society.
Instead of ridiculous ideas intended to force people like banning contraceptives (which will only engender public anger and ridicule), a much more effective way would be to manipulate them into wanting children and easing the economic burden of having them.