I believe Marvel Studios could manage having two young Black women who are geniuses in the MCU, and still find a way to make them both interesting characters. We didn't question Stark, Banner, Pym, Peter, Selvig and others co-existing, so I don't believe this should be any different.
(And I'm not saying RiRi should debut in a Black Panther film. I mean, if she does, fine...I don't have a problem with that at all. I'm just saying it's not necessarily where I would think she'd make her initial appearance.)