Globalization like China's activities in Africa depend on resources China does not currently possess like a blue water navy formidable enough to secure its lines of communication absolutely vital to it. All globalization including China's is possible due to US tax payers footing the bill for this Cold War arrangement where the US guarantees safe seaways for the capitalists and participants of Bretton woods. This system has been on the decline since the 1990s. Trump and Biden are both been investing less in global security than their predecessors.
The continents are likely to become less connected going forward.
Also, I find it unlikely that the Chinese would open to hundreds of millions of young Africans immigrants to replace their children.
They don't have to. They are setting up schools, hospitals and training in Africa. They plan on moving a lot of their production there I assume, which is what the west did with China.
If that's their plan how to achieve geopolitical dominance, I'd say it could become difficult to implement. Energy from the Middle East, production in Africa, and consumption in China. No blue water supremacy and surrounded by a chain of major islands inhabited by people deeply suspicious of them or by traditional enemies.