Oops, My Heart is Beating (2020)

Both are love stories between a ruler and his servant. Both FLs are considered unlikely love interests (disguised as a male vs. a "plain" maid).

Both are love stories between a ruler and his servant. One is fantasy, the other only historical but both have a similar feel.

Both are love stories between a ruler and his servant.
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Both are historical dramas in which the ML is a king and the FL is his servant or working for him in the palace. Both have a scene in which the bad guys suspect the FL's identity and abduct/torture her and the ML arrives to rescue her.

-Quirky and strong heroine.
-Smart and respectful male lead.
-Side characters help build the story.
-Good pacing.

FL (in this case a physician) who loves money, disguises herself as male and ends up close to the King.

Both dramas tell a story about a girl dressed as a eunuch and her romance with a handsome king. Both are historical romantic comedies.

Same girl dresses as eunuch and falls in love with the emperor storyline. The only difference is that Splash Splash Love has time travel genre.