You don't have to jump right to one child per household (which is a bad idea anyway) but maintaining sustainable population levels should extend beyond just border control. It should include things like building out infrastructure in underdeveloped areas and encouraging (or perhaps even requiring) people to move in the new spaces, enabling and encouraging remote work to free up unnecessary office space and concentration of workers to city centers, and the promotion of sex ed, family planning, and birth control so that the children being born are going to parents who want and are ready for them.