I confess I am mystified as to why a black actress was cast in the role.
If it is, as may suspect, to make some utterly pointless right-on woke point about equality, then it is ridiculous.
Making a point anywhere at any time only works if your point is what people see, hear and remember, and not the controversy surrounding it, that drowned out your message and made sure only the controversy remained.
My view is that I have no real opinion either way - I am sure the lady will aquit the part perfectly well, and I will try not to be distracted by her ethnicity, and let it spoil my enjoyment of the drama.
My wife on the other hand, who is a serious student of history, and can spot an inaccuracy several miles off, may well struggle with the notion of a woman who was clearly and undoubtedly white skinned, being portrayed my an actress with black skin, with no discernible improvement in conveying the history or the drama being portrayed.