Qin Ai De Wu Xiong (2021)

Both stories start with a contract between the main characters agreeing to be brother and sister. Both are also Chinese historical romantic comedies.

Both FLs are from modern day and meet the MLs who are in/from ancient times. Both MLs are supernatural beings whose life is tied to a tree, with the tree reflecting what happens to them/how they're feeling (blooming withering, etc.).

Both FLs are from the modern day and magically enter a fantasy historical world with sects, romance, and tragedy. At least one person close to them from the real world later enters the world as well. Both FLs love milk tea and create or have a version created for them in ancient times.

Both are about a talented ML who are socially akward (in the case of Love and Redemption its because the ML has a stutter) Both ML are prohibited by their master/sect from associating with women

Both dramas are light and fluffy historicals with a non-human ML and an endearing FL who has come from another place (heaven vs. the real world).

FL travels from modern day to historical times. ML is unique in some way (strange illness vs. being non human) and intrigued by the FL before he falls in love with her.

I'm on episode 3 of Love is Better Than Immortality.

Both shows have a fake sibling relationship.

In My Dear Brothers, it's because the male lead had never been around a female before so was confused and ignorant about different male/female relationships.

In Love Better Than Immortality, it's because the female lead lost her memories and the male lead is pretending to be her brother to get her to steal something for him.

In both dramas the main couple have a fake brother-sister contract relationship that turns to romance.

Both are mini dramas in which the leads are non blood related siblings who fall in love.
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Modern day FL travels to historical world and falls in love with the first person she sees there. Both dramas have the same fluffy endearing tone and sweet romance between the main couple.

Both are fluffy dramas with a modern day FL entering a historical world and falling in love.
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Story plot is almost the same. Time travelled thru a pothole of water. Main couple in both dramas ended up together in the modern times.
Both dramas are definitely must watch.

FL travels from modern day to historical setting, meets and falls in love with ML. Both are fluffy, light dramas with a quirky and adorable FL.

The storyplot of FL being able to transport into a parallel world from contemporary to dynasty era and vice versa. Same goes with the ML, from dynasty to contemporary era.
The romance is almost the same...and yes, the fish kisses are just the same too. ?
Both dramas are entertainingly good. Even the humor are onpoint.

Both ML's are kind of special. In YSMD the ML doesn't have senses, doesn't know emotions and he's kind of innocent to love because of that. In MDB the ML has the same innocence, he doesn't know how to differentiate emotions especially love. Both FL's arrive in unfamiliar surroundings and want to escape as soon as possible but end up slowly falling in love with the clueless ML.