hey so because i can see youre asking mostly out of curiosity and in a polite manner i will try to do the same in my answer, forgive me if i sound a little tired with this as ive answered this question a few times from people who have a lot more racist undertones.

theres 3 parts to this answer to consider: the real life one, the context surrounding POC blake and of course my own personal views.

1) Your knowledge on asian people seem a little skewed towards light skinned asian cultures and presentation but rest assured the tone of blakes skin in my depiction is one that can be found in many asian countries such as cambodia, vietnam, malaysia, philippines and more, in fact i wouldnt even put this skin tone down at all as african unless youre talking african american etc bc many african skin tones are far far darker than this.

2) SO when rwby was pretty early on as a show a lot of people werent impressed by the total lack of diversity in the show. If you rewatch rwby s1 youll noticed that apart from a few asian keyed characters (ren being the main with blake and cinder being suggested but you really didnt know at this point) there are absolutely no people of colour. like none. not even emerald. and so a lot of fans took to Blake as she has a lot of motifs attributed to being a person of colour (the fact of her being part of a minority that are often treated inherently as criminals and of course her colour association being black). so a popular trend of Black!Blake grew out of these circumstances and remained popular still after the increase in POC characters! (which i support as theres still a pretty meh amount of diversity)

3) my personal view on blake is definitely that shes asian too! my personal favourite headcanon however is that shes a mixed race girl so black and asian. Regardless these views I still draw her in a skin tone that i dont consider to be that close to african? like with her skin being darker in s4 as well as her mums darker skin tone i feel like my art comes in pretty accurate to how she looks in the show?

Sorry for the paragraph answer! I hope this brings you some understanding.