Responses
Well the main reason for many long standing webtoon with 30+ (especially this one with 100+) chapters is that the artist's style simply changed/developed.
This series has been on going for years (earliest fan translation on this site is 2021) so it makes perfect sense that the artist style wouldn't be exactly the same.
Other factors could be faster development can also tweak the style
Can someone help me explain why the art style of this manhwa changed?