Just thinking about how racist manga readers and anime watchers complain about Black people who don't want to be represented in the artwork as a stereotype whether that be in features or behavior. I personally think mangakas should forego adding Black characters at all if it's going to be a poor representation. Poor representation is the same as no representation, and tbh, I don't need to see any images of myself in a Japanese cartoon.
On another note, Black artists who do fanart of characters but make them Black are well within their right. People have been doing fanart for ages but once a Black person does it, everyone loses their mind. Just move on if you don't like it. Black people aren't saying their Black characters are better than the original. It's ok for people to say "I like this version of so-and-so character", doesn't mean that anyone is claiming it to be better than the original.
Anyway, no matter what anyone says, Black people are gonna keep reading manga and watching anime and enjoying it, so the people who are mad can stay mad.