I think I heard North African slave traders may have enslaved more "whites" than the number of African slaves ever brought to the US. Not sure there is any money to get from North Africa these days.
Supposedly, around 200K black slaves were imported to the English Colonies and the USA total. Our black population decends mostly from this 200k.
"Up to" a million Europeans were kidnapped and shipped to North Africa (note these are probably mostly captured by Arabs and other North African Caucasians, not black Africans... and the exact number is obviously unknown).
There were a large number of black slaves imported to the Caribbean and South America... much, much more than were shipped to the English colonies / USA. More black slaves were shipped to Jamaica than to the USA.
Regarding black African slavery:
The largest group of black slaves were owned by other blacks in Africa. These tended to have more freedom than black slaves elsewhere, but they were also used for human sacrifice at times. This is an interesting article about the practice:
https://www.newyorker.com/culture/personal-history/my-great-grandfather-the-nigerian-slave-traderThe second largest group were shipped by Arabs to the middle east and North Africa. Blacks are not very common in the mid east today, because the Arabs would castrate the male slaves. Arabs would breed with the slave women, so there is a genetic legacy of black ancestry in the Arabs, but since it is a relatively small percentage, not a lot of them are identifiable as black.
The next largest group of slaves went to South America and the Caribbean (I can't remember which got more).
The USA got the least, around 200k.