You're trying to move the goalposts. We're talking about the future and how birth rates are trending. Now you're trying to change the conversation to the present, "Are you suggesting that birthrates don’t remain high in the global south?" Obviously they're higher in some countries, but those rates are collapsing like they are everywhere else. And there isn't a good match between those countries and what is usually described as the global south.

Since you're too lazy, I did your homework for you: https://www.statista.com/statistics/1034075/fertility-rate-world-continents-1950-2020/

You can look up more information here: https://www.birthrate.io/fertility

We're talking about the future need for workers, not the present. So please don't try to move the goalposts by asking the obvious question of are birth rates still higher in the SOME PARTS of the global south relative to the north.

But there's a very clear trend here. Every single country undergoes a decline in birth rates as it industrializes. The global south is not an infinite source of labor you can rely on forever.

You need to let go of this myopic North/South, Imperialist/Colonized framework you seem to be trying to shoehorn into every problem. Here are the countries that have above replacement fertility rates (in green):

There's no real connection here between these countries and "the global south." Counties such as India, most of South America, Iran, SE Asia, etc are all below replacement rates.

Here's what fertility rates are currently projected to look like in 2100:

We're on track to have less than a handful of countries around the world with above-replacement fertility rates. The global south doesn't have elevated fertility rates, the specific regions of Subsaharan Africa and Central Asia do. Even Somalia will barely be above the replacement rate.

You're too lost in a surface-level understanding of "theory" (read: socialist memes) that it's clouding your judgment. Within a generation, countries all over the world, including countries in the global south, will be fighting each other to attract immigrants.