The director is an arthouse director who doesn't normally do period movies - I haven't seen any of his other movies, but the arthouse background was pretty clear.
But when you look past the oddities with the funny camera angles and the title cards, amid all the obscenity and crudity you do get a pretty interesting take on the unusual power dynamics between a 'favourite' and her/his monarch, I thought. The way Sarah can reign nearly absolute in court and even Parliament, and even gets away with ordering the queen around, until the moment that she pushes it too far and then it's all over in a moment. The manipulations of Abigail and the way she works her way into the queen's good graces in her ultimately successful attempt to displace Sarah - but then before she can aspire to wielding power the same way Sarah did, gets brought down to earth by the queen and reminded of her position, in the closing scene of the movie. The queen's traumas and volatility, being constantly flattered and manipulated into following her favourite's or her ministers' wishes, but still ultimately holding massive power when she dares to exercise it.
You could've done all that in a more conventional and less crude movie as well, no doubt, but not too many conventional period movies are as strong as this one in illustrating this kind of thing.
My understanding is Sarah was Abigail's first cousin on her mother's side, while Harley was her second cousin on her father's side. So the latter isn't actually closer than the former, then?
But yeah, either way, perfect historical accuracy about Queen Anne, Sarah and Abigail clearly isn't the first priority.
It's a pretty hard movie to pin down, but it definitely offers a lot more than just shocks and crude laughs.