@Aldis
I feel that the comic did not explain further about the family situation clearly (or that might also the novel's fault).
So the illegitimate daughter got mistreatment from the servants.
Why the eldest daughter wasn't aware?
Why the eldest son stated that he 'leaves Lilian to deal it herself'?
Did Lilian join the household already as adult teen? Does eldest son want her to stand up herself? (If yes, it can also be said that the eldest son is apathetic but he doesn't seems like one.) Does the mistreatment is actually hidden from the public eyes? Or did MC already regain her memories and planned her way out thus revolt against servants probably useless?
(It seems like I answer my own question, but seriously, the comic did not elaborately the background clearly)
@Akera93 lololol totally agree with you
But if we exclude the problematic plot of Chinese webnovel/toon, the Korean ones also starts to repeat the same trope (currently, dungeon RPG style and isekai'ed princess or ladies). They also loves using the overbearing CEO (now in prince/duke version). But yeah, generally it's better and even there's romanticized abuse, it written well. (This is also a rant hahaha)