Population control is on the top ten of the stupidest policies ever conceived - and that's a very hard thing to achieve
We can discuss it theoretically, but there is no need - take a look at China. With their one-child policy, they did manage to stump the population but turns out that their population is now destined to have a much higher average age. Which means that their economy will shrink (someone has to work to support all those elderly people) and people will become poorer. And it's so utterly absurd, that even they had to reverse course, scrap the policy and try to make people have babies - which will take time and effort because 30 years of indoctrination of how bad of a person you are if you have babies isn't going away magically in the short term.
So what is the right policy? Again, we could theorize but there's no need. We have tons of empirical examples. Take a look around: all developed nations have a population shortage. As a country grows rich, people suddenly lose incentive to have lots of kids. Therefore, policies that increase wealth are also solving the population issue.