Start with high-confidence historical ya - africa books, then narrow by subgenre or adjacent topics.
Buried Beneath the Baobab Tree
Adaobi Tricia Nwaubani, Viviana Mazza
Chike and the River
Chinua Achebe
Copper Sun
Sharon M. Draper
Black Dove White Raven
Elizabeth Wein, Lauren Saunders
A Bone From a Dry Sea
Peter Dickinson
