I don't play Genshin either but it's disappointing how Latin America is barely acknowledged outside of our own territory and every time we get something overseas, it's either reduced to "brown savages" or "white wearing stereotypical clothing". Yes the way "race" works here is quite complex and here in Brazil specifically it's more about how you identify than how you are physically since most of us are mixed in some way, but it won't kill anyone to have more characters with a bit more Melanin on them or even visible ethnic traits since having lighter skin doesn't mean you won't have other physical traits.
I myself am light skin but in that weird field of not being dark enough to call myself "parda" while having facial traits that makes the racist idiots here ask if I'm asian because they never looked at any of our indígena population. Me being closer to what could be considered white in the Northeast of Brazil in special does not change the fact that the majority is not like me and that even if you're "white" in one location, it might not be enough in other regions because you're clearly racialized. Yes, if you live in those rich neighbourhoods filled with I-Hate-POC-nium you aren't going to see the melanin they hate so much, but that reflects a much bigger social issue.
Also within the same mixed family there will be multiple different traits, my older sister is dark skin and considers herself to be black so it is really weird how the game will get multiple new characters and none of them has darker skin.
It really is disappointing. I do remember seeing multiple videos of "skin-whitening soap" back when I still used social media so it is a general problem. As the other users pointed out though, it's money that decides what we get. At least sometimes things like Michiko to Hatchin or even Giovanna from Guilty Gear pop around.
(My apologies if anything I said sounds weird I don't talk about those things in English so there could be some nuances I'm not aware of lol)