Both are short and sweet historical romance dramas in which the FL ends up entering the ML's family under a false identity, but the two fall in love.

Forced marriage turns into true love (in TDS the bride is switched, in GL its the original bride). Both have the same actor as the ML and are historical romances.

FL switches identities with another girl which results in her becoming the ML's bride. The two end up falling in love.

FL ends up unexpectedly married to the ML, which grows into love. Both are enjoyable fast-paced historical romances.

Both feature a bodyguard/princess romance although the dynamics are very different.
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Both have similar pacing, vibes, and aesthetics. The ML quietly follows and protects FL who over the course of the story grows into a strong character.

FL enters a different world and unexpectedly falls in love with the villain.
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Both are short length dramas in which the FL finds she has become the heroine of a fictional story (novel vs. manga) who is fated to die tragically. In order to try to survive she turns to the villain responsible for her death, which leads to changing the plot and unexpected romance.

In both the FL finds herself a character who is fated to die in a fictional world (novel vs. manga) and ends up getting close to the villain in order to try to change her fate and survive.

Both dramas take place within the world of a manga. The FL is self-aware, trying to change her story. In both she suffers from heart disease and falls for the ML who is an unexpected choice (minor supporting character vs. main antagonist) and who can help her in some way (change the story vs. ease her heart condition by kissing her).

In both, the ML is a character in a manga.
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Both are short length dramas in which FL is a self-aware manga character trying to change her story.