So from watching the video... I haven't seen The Woman King, but complaining that Black Panther doesn't realistically represent modern African countries is just stupid. Wakanda is a fictional country from a superhero comic book. It is intentionally unique and fantastical, with its own religion and crazy technology. I'll admit to some bias since I love the comics - particularly the Christopher Priest run from the 1990s - but this seems petty.
The Black Panther comics and the Black Panther movies shouldn't have to represent all of Africa. I can see complaining that modern African countries should be better represented in movies, but I don't think Black Panther should be expected to do so.
I'd complain much more about movie adaptations set in real African countries, like Black Hawk Down. One of the fascinating parts of that book was when it interviewed local civilian residents who were on the scene as the military action was going down. But that side of the story was completely cut out of the movie.
You're completely entitled to enjoy Black Panther and Wakanda, but the big problem with it is not so much that it doesn't reflect the reality of Eastern Africa, but more that it's an ethnonationalist state; Back when the first movie came out, people were memeing “Make Wakanda Great Again” to hell and back. If we think that ethnonationalism is a dangerous cultural/political position, then we ought to decry it when it happens in Africa just as much as when it happens in the United States.
If ethnonationalism is just as valid as social democracy, then sure, Wakanda away. But then other ethnonationalist states in fiction also get a free pass.
Wakanda is extremely isolationist, but it isn't ethnonationalist. At most, it is a parallel to Japan.
It does not recognize race legally, and there has been no mention of it culturally. In the MCU thus far, the only outsider invited to live in Wakanda thus far is a white man -- Bucky Barnes. Two outsiders were allowed to visit under exceptional circumstances -- Everett Ross and Riri Williams. However, they were kicked out afterwards -- and with both, it was seriously discussed whether they should be killed. I don't see anything to suggest that their race ever factored into either discussion.
The whole point of the first movie was that Killmonger believed in Pan-Africanism and unity among black people. He took over Wakanda to pursue that agenda -- but that was from his unique upbringing in America, not an internal Wakandan idea. It was rejected when he was overthrown. Except under Killmonger, Wakanda hasn't shown any favoritism towards African countries compared to any other country.
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In the comics, one of the only outsiders to grow up in Wakanda was a white man, Hunter, whose family died in a plane crash in Wakanda when he was a baby. He was adopted by the royal family and grew up to be head of the secret service, known as White Wolf. (In the MCU, Bucky Barnes is supposed to be a parallel for this character.) In the comics, Hunter suffered some discrimination growing up because of being an outsider, but he had full legal rights and was considered fully Wakandan.
There also isn't any identity of Wakandans as being a distinct race superior to other Africans. Killmonger's mother was American -- but nothing was made of his mixed parentage in terms of how he was seen. They questioned him for being raised outside of Wakanda, not over his race. Also, the MCU version has been clear to portray Wakanda as multi-ethnic internally, particularly the Jabari clan. It was implied that they were seen as strange backward hicks for their ways, but they still had full legal rights under Wakanda's constitutional monarchy.