Lands, titles, wealth passing through the paternal line seems like it was simply made up to be a plot device. Like simple logic would dictate that if it’s important to you that something stay in a family line, then it should pass through your mother. I know who & where all my children are. There aren’t any extra bastards who could claim what rightfully belongs to them & no one could question who their mother is.
I’m asking authors to let this silliness go. There are other ways to tell a story.