Take the concept of generational wealth or other privilege, and apply its inverse. Now woke academics likely overstate this effect, but you can see generational poverty in white families too.

Now, slavery ended a long time ago, but Jim Crow was much more recent. I'd say this recent economic inequality has more to do with the current situation of blacks than slavery.

As far as your Africa argument, better material conditions are not a justification for slavery, or a moral license to abuse people that otherwise would have less material wealth, there is more to well-being than that