Apparently she used an accent/dialect different from modern expectations for that historical period. Since I can't…
To answer your final question, I recommend this Youtube video called "How Netflix Ruined Korean Dramas Forever" by Asian Boss which I found interesting. https://youtu.be/p1_j6izmEX4?si=nLOVduDpeYsvfKCw
PLEASE, could someone with admin rights complete the Cast & Crew section? The director and scriptwriter was Wang Zheng. He really should be credited because he did an outstanding job of creating a uniqur universe.
https://youtu.be/p1_j6izmEX4?si=nLOVduDpeYsvfKCw