China has more people than the entire continent of Africa. Plus they have lots of cash, and lots of very smart people.
All they have to do, when they encounter any group or faction which give them trouble, is to discretely supply some rival faction with cash and arms, and have it be understood that the troublesome faction is to be completely exterminated, including the elderly and the babies. The prettier women may be distributed among the victors.
Repeat the process until there are no more Africans left.
Possible, but today’s Chinese aren’t that ruthless.