I would recommend clarifying whether you mean "DNW: fic that imitates the style or format or narrative voice of the canon" (e.g. you're requesting a Dickens novel but you don't want the writer to try to sound like Dickens), or "fic written in imitation of some other work's distinctive style/format/narrative voice" (e.g. you don't want your Ted Lasso fic written in the style of Jane Austen), or both.