I get what you mean with the not white-washing Feng Xin and to depict him correctly. But at the same time, most stylistic characters have big eyes - clearly Japanese characters from anime too, for the bigger part (just an example, I know he’s from China, but these characters, they’d have Japanese features too in reality, but in anime it’s stylized, e.g. demon slayers (or the Anime about the Chinese MaoMao)). The Donghua of tgcf too. They convey culture and identity more through clothes and hairstyles than through the eyes.
Also, many of the fandom don’t make Feng Xin white, but keep his canon a bit darker wheat-colored skin tone. It’s very probable that his ethnicity is that of a minority.
If it’s a realistic depiction, the eyes should probably be adapted accordingly. But in stylized works/caricatures of them, is it necessary? It could very quickly lead to people accusing other people of making caricatures of Asian features too, in the stylized format. And I think that would be worse and would hurt the fandom.
What do the Chinese fans think?
Firstly, I didn't bring up eyes in my original post. Thinking that in order to draw an ethnicity or race, you must include a specific feature (such as a certain shape of eyes) every time, is not a good method and can even lead to the spread of racial caricatures as you've mentioned. For a similar reason I didn't bring up skin tone, because skin tone alone is not a good indicator of ethnicity. Asian people can also be naturally dark skinned or tanned, even some white people can get tanned.
In the end, we have to do our best when drawing to create a overall impression that suits the character. My point was that people have a tendency to draw FX with a combination of many physical traits associated with whiteness, which create an impression that he's been drawn as white.
Donghua and anime are primarily created for East Asian audiences and the 'default' stylised character is intended to be read as East Asian. In the context of cultures where Asianness is already the default, there is no need to specifically avoid whitewashing Asian characters.
Here on the English speaking side of the fandom, we have to care for our own community, which is more international and includes many more people (including Chinese diaspora and other poc) living in cultures with the type of racism that values whiteness and leads to whitewashing. In this context, seeing familiar characters being whitewashed can create a sense of hurt and alienation (or whatever, I can't speak for everyone). Let's be mindful and try not to hurt our fellow fans like this.
To be honest, the choice of which characters within a canon get lightened hair/eyes/the whitewashing treatment is also something that displays unconscious racial stereotypes but I won't comment further on that lol because I don't keep up on multi fandom trends