Look, unlike some of the other comments, I don't care that MC and ML are step-siblings.
BUT the one thing that really grinds my gears is the way the FL spends so much time with the duke, because how are you going to be all close with a man who abuses his son.... Also she doesn't even berate him for it?? She's just like "we should all get along" like BE FR he's the guy who ABUSES A CHILD because of a generational grudge??? He didn't even get a slap on the wrist — the whole thing was just brushed off without him receiving any repurcussions at all!!
Also she never even addresses the root of the abuse/hatred the duke has of the ML like it's so obvious the duke still bears dislike towards the ML but she's just like "welp he's not physically abusing him anymore so it's all good!! We're all one happy family!!" Like are you taking the piss rn.....