While LLTG does not have an enemy-to-lover trope like LoN, but everything else is almost the same.

-Both ML had to take on different identities (or disguises) growing up in the imperial court in order to investigate the truth about their past family's murder/injustices
-Both ML are screwed and scheming minister/military positions
-Both ML lies and manipulates the FL in their plots and quest for revenge

-Both FL are normal but very smart, witty girls who yearns for a carefree life with freedom.
-Both FL are their own character and person and has a very clear understanding of priority between love, family and responsibility. Meaning they don't go crazy over guys, are rational thinkers and always has a sense of independence.

-Both dramas are slow burn romance
-Theres about a 10 years age gap between ML and FL in both dramas. Both FL are quite young, its like their coming of age story where they get embroil in the MLs' worlds.

Both ML was diagnosed with ALS and what follows are their journey and struggles with the disease as well as how it affect everyone around them. Inspiring stories where they try to live life to the fullest with the help of their family, friends and loved ones

Tissues required. Bucket load of tears guarantee.

If you're looking for romance tragedy...
-ML in both dramas took advantage of their FL, then take over the others' tribe/country and killed her loved ones and people.
-They also uses other women to further their ambition.
-Yep, both MLs are possessive jerks.
-Both FLs because of duty and responsibility to save their people, refuses to be with ML and rather sacrifice themselves.

Both MLs are part of special forces that protects the country and often has to leave on confidential secret missions. Both dramas MLs and FLs have to overcome their differences in profession, lifestyle and family in their journey to loving one another.

If you enjoy family business drama and family tearing each other apart over company assets and inheritance.

Both are stories surrounding rich families who tries to expand their business empire especially around automobile.

-Both has Conglomerate families that contribute to the rising industries in South Korea before the 21st century.
-Main leads goal is revenge
-Both story spans over 2-3 generations

-Main couple in both dramas were complete opposites and were at odds with each other in the beginning, with the Male Lead secretly holding a crush on the Female Lead.
-Both Male Leads are smart. One being a born genius with high IQ/photographic memory and one is a jack of all trades. Both decide to lay low in life being freelancers and unemployed due to their own reasons.
-Both Female Leads open their own practice to realize their dreams. Both have a strong sense of justice, are honest and straightforward. Once they realized their feelings, they waste no time to confess.
-Once Main Leads officially become couples, they turn into sweet, fuzzy, cheesy and cringey couples where bystanders gets sick of how lovey dovey they are to each other. Which in it itself was hilarious to watch but also give you a warm and happy feelings.

Both are romantic comedy at its finest.

If you like protagonists that uses the law to punish the villains of society, no better dramas than these two, and no two dramas are more similar in theme. Not to mention both our protagonists are Judges.

Juvenile Justice focuses on the young delinquents who think they can get away from being punished due to their age; while Devil Judge focuses on the rich of high society that thinks they can use their power and influence to commit crimes and abuse the common people.

You will feel the satisfaction when both our protagonists tear down the facade of those hypocritical criminals, bring them to their knees and hand down the sentence they deserve in court. Must I say more?

Both are considered healing dramas as the main character struggles to get over their past and regrets through their blooming love for each other and matured.

Same time travel "reset" theme where FL was mysteriously given a second chance to relive her past and change her fate.

Both original novels of these two series carry quite realistic, dark and gory undertones. Like it would depict deaths, murders and corpses in a shuddering, gruesome manner (for both bad guys and good guys alike). They censored and tone down this aspect of the story when they adapted them into TV dramas, but they still try to show/hint at the darkness in the characters and story.

Both series were very closely adapted from their novel version, so I believe this is one of the many reasons why they became such a hit.

The difference is one is bromance/boys' love while the other is romance. One is wuxia and the other is not.