Dramas Like The King's Woman + Empress Ki

I've been thinking about your quest for a while now and gone through all the dramas I watched but I gotta say,....I do not truly come up with a lot of drama recommendations.

Movies:
The Handmaiden - this movie has some explicit scenes and also some lgbtq+ topics but the story is not about that. It is a very intriguing one where you do not truly know what is going on til the end. It follow the theme of "curiosity killed the cat".
The Last Princess - this one follows the real story of Korea's last princess. it is actually quite a sad story but well done and has a lot of themes you look for.

Dramas:
Bloody Heart
Mr Queen - this is a big gamble. Not really per say what you look for since it has a body swap and a character going back to the past. But what happens in the past is kind of what you look for. Ml turns up in the body of one of the princess candidates for the crown prince and has to fight a lot of intrigues and games plus he/She doesn't truly want to marry the crown prince.


As for dramas I'd also recommend you to try some Chinese adaptions, they are mostly following the topics you wish to see.
Nirvana in Fire 
The Rebel Princess - here you have to ignore that the lead actress does not look like a 16 year old kid in the beginning. The actress kinda produced the whole drama and for some reasons did not want to have a younger actress play her 16-year old kid version so wello....plus no toxic ml per say. But they both grow into their roles and also it covers many years where the actress actually does resemble the characters age later on
The story of Ming Lan

A few weeks after I watched Empress Ki I decided to watch Queen Seon Deok. It's was a similar story in some way, so I will recommend it for you: 

Dong Yi is also one of those classical sageuk dramas that is amazing:

Also:

Goodbye My Princess