Recommendations

1. Smart ML
2. Not focused on romance
3. Intricate plot

In both cases the dramas are headed by a ML who can see through the plots devised by others and come up with counterplots.
Both MLs fall in love with a woman, but the story is not focused on the romance, and the FLs are supportive, though in JOL's case her support is through her knowledge of palace politics and analyzing plots, while in the case of IO, the female lead has the ML's back literally, since she's an excellent martial artist.
In both dramas schemes abound and are quite complex, though in IO the focus is not on court politics.

Fascinating mystery and hidden truths where you don't know who or what to believe. Traveling through uncertain times and places to find the truth of the matter, the heart of what really happened.

Both have a royal who has multiple identities. One is aggressive and one is more docile.

Difference is WUTF has a female king who has DID while in LSFI it's the Crown Prince who eventually becomes king. Both kings...

In both shows, the ML and FL are pretty down on their luck and together they’re able to get through it. Both have funny parts and heartwarming parts. Both touch on some pretty serious issues. Both have chaotic bits that will leave you laughing.

Both the dramas are based on time travel. The FLs travel to the past and try to amend and dive into a better future. While LR also focus more significantly on the present showing their story in the present, SYA talks a lot about the past. Also in LR, the FL is not directly already in love with ML, while in SYA she is. There's love triangle as well, but SML isn't strong for either.
There is a very strong message relayed in both the dramas. If you enjoyed one, you'll definately like the other.
I personally liked both. SYA made my heart ache like anything, and legally romance made me ponder a lot.

The similarities are body swapping but in 'The Day of Becoming You' gender-swapping is involved with body swapping and it's a romance drama.

Both dramas are focused on murder case and detectives trying to solve the mystery.
Both dramas were filmed in a unique way of jumping the timeline from past to present which can be rarely seen in Chinese dramas. But both have done a great job and added spice to the dramas.
Great casting for both drama. All actors' acting are on point.
Tender Light has more romance and love story between the leads compared to Thirteen Years of Dust.

Strong ML and and the FL also fakes her death, repeatedly, to return.
Complicated political struggle, and wuxia, many good battles.
Use of poisons to "control" a character.
Romance.

Uber exciting love stories, time traveling, involving love and tragedy, repeatedly trying to "save" *wink wink*, also goes back to school life then adult life multiple times

Young girl Chu Chu came from a family of coroners. She meets Prince Xiao Jin Yu, a dignified prince in charge of criminal lawsuit who appeared weak and sickly. Prince Xiao lacks reliable manpower to investigate case, while Chu Chu lacks people to step up, take charge and be a man.
Together, they manage to unravel a shocking case that has dragged on for 18 years. After solving the case, she won the Emperor's approval and is finally certified as the Imperial Coroner, fulfilling her life goal.

I mean ........

romance between the main leads give the same feel. both ml are really handsome, mature and yet goofy and female leads are more brainy. although in hidden love female lead was the one to fall in love first but ml fell harder like in sunjae

ML falls first and falls harder. Crime side plot of murderer after FL and ML willing to die to save her.

Similar to the fake it till you make it journey where the prey turns into the predator.
Boyhood is funnier and great acting with a Satori? accent.
Its in high school and alot less lighter.

Both are mini dramas in which the FL is a spirit/deity sent down to earth to complete a task. Both MLs have a "cold outside, warm inside" personality.