Africa is a vast continent, Africans constructed a vast array of social systems and structures. Some were Matrilineal some were Patriarchal.
The mistake I think we make is we imagine these terms and practices manifested the same across cultures and across continent. So have to understand that African patriarchy is not the same as Asian, Native American, or European patriarchy, and the same goes for matriarchy.
Then you have to look at the varying manifestations of patriarchy and matriarchy within Africa.
Finally you have to determine if the matriarchy or patriarchy is native to the region or culture you are observing, if it has been contaminated or influenced by foreign cultures and alien invaders, or if the current system has fully replaced native African customs and practices with a colonial customs and values.
Some will try to argue that all of Africa was P or M, but that’s incorrect. Some will argue that Africa was a utopia of balanced and exploitation-free social and political relations between the genders, that’s not true. Some will argue that women’s oppression was universal and almost synonymous with African cultures, that is also untrue. The truth is more complex and dynamic.