Recommendations

Both are Thai GL. Both have some action and a woman who protects her love interest. In Petrichor she is a police detective, in Only You she is a bodyguard.

Set during the Tang Dynasty, this series follows two officials as they unravel a series of mysterious and supernatural events, blending historical intrigue with detective work.
Lu Ling Feng, general of the Jin Wu guards was tasked to investigate these strange cases, but finds himself having to work together with his strongest opponent in Su Wu Ming, the disciple of Di Ren Jie.

Very similar premise, about four best friends finding love for the first time in high school. Biggest difference would be how in Koi ni Mudaguchi every character has a partner, while HaruDan has a bit more drama between the boys.

Both the MLs are losers in love. It has "he fell FIRST and he fell HARDER" trope. None of them get swayed by the other girl trying to stab their relationship with FLs.

Both dramas heavily use the rich/poor trope. Both the main and side couple in both dramas use it.

High Society is more drama vs. Business Proposal is a romcom.

However the real reason I link these two together is the second leads stealing these shows for me.

same couple, similar concept

......................................................................................

- the suspense
- she falls first he falls harder
- secrets between lovers
- romance/thriller/mystery (I would say WTPR is a little less intense tho)
- super captivating story

both plots envolve kidnapping, murder, mistery, a child, a loving mother willing to do anything to protect the family...

both are similar in terms of vibes and cinematography, both are healing shows, both fml are ''lonely'' characters
- the plot might not be similar but as someone that loves our beloved summer i def think u would like mln

Both are melos with strong makjang elements and similar heartwarming vibes where the FL loses everything after being rich and is now living as a poor but upbeat energetic person not realizing how much her step family from her previous life ruined her life. In both there is a very similar love quadrant where FL is having this non official relationship with the SML who helped her throughout all the hardship and keeps being her doormat while waiting for her to be ready fo him while FL is falling in love with ML who is involved kind of by default and indifferently with the woman who brought FLs demise and now lives with this dark cloud over her head desperately and unsuccessfuly trying to keep ML from going to FL...

- Slice of life
- Unconventional family dynamics (found family in TADT, role reversal in SM)
- Slight but prominent parenting arcs
- Friendship
- Girlboss x Malewife dynamics
- Light and fluffy watches
- Both short Jdramas

- Family focused (more found-family in TADT)
- Unconventional families (found-family in TADT, role reversal in SKwLd)
- Writer SML who does household chores
- Prominent child/teen MC
- Girlboss x Malewife dynamic
- Bold SFL x Softspoken SML
- Fluffy and heartwarming
- Both short jdramas

SKwLd is a family mystery comedy while TADT is a slice-of-life drama. Both are adorable and worth a watch.

Similar adaptation

Prior to the adoption of Confucianism, it was the tradition to abandon one's parents on a mountainside if they were over 70 years of age. In the ancient kingdom of Goryeo, now modern Korea, a nobleman defies this tradition when he refuses to leave his mother to starve to death.

Fantasy and supernatural themes, Complex world building, Romantic Subplots, Strong fateful characters, Royalty and Power, Visual aesthetic and cinematic style, Strong female leads.
The blend of magic, destiny, romance, and intricate world-building makes both dramas particularly engaging.

If you like one, you'll most definitely like the other.

Similarities:
- Main leads are childhood best friends
- ML has liked the FL for a long time but is too scared to admit it
- FL has trouble in her career, so the ML helps her
- Close proximity helps develop their relationship
- Love triangle (2 guys, 1 girl)

Differences:
- LND focuses a lot more on family relationships as well as romantic ones and has a more full plot with side characters that have their own story (like the main character's parents, the other bsf, and her brother) because it has 16 episodes whereas S#1 only has 4
- Soundtrack is more of a fluffy romance without much drama, but LND has a lot more plot twists and other factors to their relationships that cause a lot of delay

I personally loved both of them, but I will say that if you like shorter plots that get to the point faster and don't run you through a mix of emotions, then you should watch Soundtrack. But if you like seeing a secondary couple and also seeing the main lead's family and friends and seeing a more realistic approach to romance, then LND is your best fit. Hope this helps!