Asian fude nibs are a blast for art and very expressive!
There is one fude fountain pen that utterly stands out in terms of having insane line variation with a feed that can keep up without leaking everywhere and as far as I am aware except for some obscure Sailor nibs that are far more expensive (not the cheap sailor fude pen which is great but incapable of extreme line variation) it isn't even close.
It is the Duke 551
https://rupertarzeian.com/2024/01/21/early-thoughts-on-the-duke-551-confucius-bamboo-fude-nib-pen/