I am guessing that Yanhan's goal is to emancipate the women from their subservient roles.
It's clumsy and doesn't fit with the era or the way real women thought back then. We're being fed a modern idea about women in almost every episode. There are better ways to write this into a story.
The right way to script a mystery/suspense drama is "Show, Don't tell" which is not happening here. The viewer is being given information forcefully only when the characters confront each other. It's become tiresome and insulting to a viewer's intelligence.
Surprisingly, the only consistent character is FL's father. Yes, he's not innocent and guilty as hell but least his character arc makes sense and is clearly written. The rest aren't as convincing.
Historically speaking, eunuchs had a lot of adopted sons or nephews from their cousins and blood relations. So yes, it doesn't make sense he'd have only one son.
The tonal shift between the first and second half of this drama doesn't make sense. And all these heavy-handed feminist messages feel like the scriptwriter, who is a man, is ticking off issues from a list.
Ep.16: if this was a story about the mother, I'd probably be more interested. Her "friendship" with the Consort and her own lover are more interesting and layered than FL.