How do US investors here get real exposure to frontier markets like Nigeria, Kenya, or Ghana?

Not talking about the broad EM funds, where China, Taiwan and Korea eat most of the weight. I mean actual local-exchange exposure.

Full disclosure so nobody wastes time: I work on market infrastructure in this space, so I have skin in the game. I’m not linking anything and I’m not pitching.

I’m genuinely curious whether US retail investors want this at all, or whether the access problem exists because the demand doesn’t.
If you have looked into it, what stopped you? Custody, FX, tax reporting, or just not being convinced by the thesis?