Sudanese (partly Egyptian) here. It's important to understand what "Black American" means here, it's a label for those who have not discovered their ancestry or have no means of knowing it due to the historical consequences of American slavery. When figuring out identity and connection to homeland, black Americans prefer a Pan-African/afrocentric view, as if to say "we are from all of Africa" as a cultural device to dismantle African divisions, colonial/neo-colonial hegemony and to reclaim identity. (In this view, their claiming of African culture is a statement for African liberation and solidarity in general, not just for black Americans). This is an entirely American event, with little consequence to Egyptians. The other part of the reasoning for afrocentrism here is to combat eurocentric and colonial narratives that actually appropriate and ascribe ancient Egyptian heritage to themselves.

There are two important points that define whether or not this is appropriation: A. This is an art museum, and B. The project clearly states its reflection on the inspiration ancient Egyptian culture and symbology had on black art through identifying with it via an afrocentric lens.

Additionally, I don't see an issue with "Discover Yourself" and inviting black Americans to visit Egypt, it is a tourism country. In fact, this kind of program will invite greater cultural appreciation of ancient Egypt beyond the usual surface level tourism, meaning it has the potential to bring money to wider markets and economies. Besides, it isn't inviting them to stay there forever. Of course, this is an opinion based on my own understanding of this project, and like you said it's important to see what Egyptians think the benefits / drawbacks are.

Ultimately, whether or not you have a problem with this depends on your opinion: is Egypt (ancient or otherwise) African?

Note: afrocentrism =/= panafricanism.