I'm not surprised that Black US kids don't perform as well as white US kids, or as well as Nigerian, Ghanaian, Kenyan, or Caribbean kids. I'm surprised that any Black kids make it through this hellish gauntlet at all.
When you look at how much the US pays to educate each student, and how poorly it does at Black educational achievement, it's clear that the US is the worst country in the world at educating Black students, by far. Because racism. No one spends more to achieve less.