Ignoring how you ended your statement.
It is naive, so so so naive to believe that "open ethnicity" actually means they will cast a poc or rather that they would actually consider actors of color for the role. Not to say that's what you said or implied is gonna happen but people should keep this in mind.
When castings say "open ethnicity" it's usually just for show, ...not to say all of them are like that but most are, especially when they (tptb) already have an idea of an actress in mind; example being Chilling Adventures of Sabrina who also had an open ethnicity casting and after hiring Kiernan Shipka, admitted that Kiernan is who they envisioned from the beginning and wanted.
I would be shocked if they cast an actress of color but if they did I would expect a latina actress like Bella Thorne or a black actress like Zendaya, since they are not that big of stark contrast complexion wise from the comic version.
More than likely a poc on this show would be relegated to the best friend trope or they'll have her step family be biracial with the step dad being white and the biological mom of the step siblings being a woman of color.