I wouldn't even say it's just an issue of this book but if you read and watch enough Korean Dramas, you see this common trend of "bad parent, bad child". I see it in the Chinese ones too. Hard to say but I think it's a reflection of their collective mindset as a society that seeps its way into their literature.
Like if you watch the classic Korean Dramas like stairway to heaven (way more dramatic than this korean comic lmao) the Villainess also has a "Evil mother" meanwhile the female lead's parents are "Good". The brother who is good also conveniently is raised by the dad that is "Reformed and Good". Moon Embracing The Sun also has that good parent good child and evil parent evil child theme.
I've just never read a manhwa where it's THIS prevalent. And the acting in kdramas is just a little too theathrical for me most of the time, so I have a hard time getting into them. And if it's not the acting, then the editing
I hate how this manhwa pretends personality traits, interests, and talents are passed down genetically, even though it's such bullshit.
Also if the shittiness is just inherited that means it's not Eunhye's fault she sucks, she was just born that way. That's bad. She should be responsible for her own actions!!