Preference for the Posessor although it doesn't really focus in their family dynamics but you can tell that there's no preferential treatment even knowing mc is powerful. Her dad is mostly mellow and her brother is a copy of her dad
Adopted by a Murderous Duke Family, My Father Is the Enemy of My Past Life? (art style is beautiful, so adorable too), I'm the Heiress of a Villainous Household (Also super pretty art style).
My Mom Entered a Contract Marriage I think could count too? Since the “son” (he’s a nephew) is pretty cold but after FL comes the emperor warms up to him too. And they all become more of a family.
Does anyone know other manhwas where the children are loved equally? I hate those tropes where the father and son compete for the mom's affection or when the parents only dote on the MC