1) They need to drastically cut social welfare and make it harder for females to live independently of men. Social welfare is a moral hazard. People will forgo forming relationships for financial security if they can get it from the state. Ironically, this reduces future state revenues in the form of poorer households and fewer children leading to an aging society.
While reducing the role of the government in society, religious organizations such as churches, since Korea already has a tradition of Christianity, would pick up up the slack and bring people back to a more wholesome and natalist point of view.
2) Females need to be drafted into a form of social service, commensurate with the time men spend in the army so they cannot advance too far beyond men. Females are not attracted to men they make more than or careermog. It’s not a coincidence that the nations with the lowest TFRs are Singapore, Taiwan, and South Korea. Similarly, Switzerland’s native TFR is low and the nation’s fertility rates are buoyed by immigrants who make at least a third of the country. These nations’ mandatory service for men exacerbates an already bad problem.
3) In order to accommodate demographic shortages, they should prioritize females from less Western and/or more religious nations, and expedite residency based on being in a relationship or marriage for a given period of time. Demand the couple pay a significant amount of money (50/50) and keep it in escrow. If they break up before a certain period, the government keeps the money and she loses her residency permit. Essentially, recruit foids via a temporary work visa, but make their quickest and easiest path to staying through maintaining relationships and not through employment.