Responses
I think you don't realise just how big ORV actually is in South Korea. The franchise includes webnovel, ebook, webtoon, films (if I remember correctly, 5 are planned) and potentially anime.
The novel 'Quack Healer' started releasing later (2021), so it appears the design was a deliberate choice. Sure, one may argue that short black hair and black attire with a white coat look quite generic, but at this point, it's too recognisable. Could be some marketing strategy, who knows.
orv fans just read something else if you're gonna complain about his character design if they're from the same studio then it wouldn't be weird that they got inspo from orv but also his character design is literally so average like he has black hair with black eyes and a white coat because he's a doctor