Recommendations

While very different plots, both have a similar aesthetic - dark, rain-drenched, cyberpunk-like sci-fi. Both FLs have deceased fathers who created or worked on some project that the FL has now discovered in the present. Both MLs are somewhat dangerous and the FL is suspicious or antagonistic to them at first.

Nothing similar, actually. Unchained Love can actually be used as a refresher if you are tired of this damsel in distress trope which is annoyingly used in MTD lol ?
Here, our male lead has a more layered character while the female lead acts dumb and naive but is actually really smart!

Simmilar theme, same vibe, not many episodes, great acting, not much censorship and weird scientific mackgroud and explanations.

Beside both are the bl romance genre, they are about living out the last days before the world ends.

same vibe of helping dead people

If you liked LLGT then you will definitely like the lighter & princess. Even though they have different genre and plot but chemistry and tension between lead is same. Li Xun and Ling Buyi are very much similar, they both love their FL to the point they can do anything for them but at the same time hide many things from them for their safety. Zhu Yun and Cheng ShaoShang also have many similarities, they are headstrong and can fight with anyone for their love, they both support their partner selflessly. They both have mothers who try to take control of their life and supporting father. SML in both drama are reliable friend for them after separation in drama.

1. Strong, smart female lead
2. Mature and caring male lead
3. Older women younger man romance
4. Slow-burn romance
5. Misunderstandings cleared up quickly

- Both MLs are anti-heroes considered as the bane their world
- Both FLs start off as having prejudice against the ML
- Both MLs fall in love with the FL first
- Both MLs does everything to protect the FL even though they might get misunderstood

- Both MLs are seen as evil (one thru his deeds and one thru his bloodline)
- Both FLs start off as pretty innocent/naive
- Both MLs fall in love with the FLs first

- Both MLs are considered evil by most of the characters in the series
- Both FLs start off very naive, and prejudiced against the ML
- Both MLs fall in love with the FL first

- Both MLs are viewed as ferocious lords/generals
- Both FLs initially had a bad image of the ML because of the rumors
- Both MLs fall in love with the FL first
- Both MLs are domineering
- Both FLs like food (one is a foodie while the other is a Michelin Star cook)

If you liked the anti-hero ML, you might watch TLLoQL but in the point of view of the “others” who view the anti-hero as a villain.

The “villain” in TLLoQL is like the older version of the ML in DL.

- both are workplace romcoms
- formerly married main leads(time travel is the tool used to un-marry them here)
- Jang Seung Jo stars as a side character(ML's dorky, adorable best friend)

Both have themes that revolve around woman in a care center focused on treatment of pregnancy issues.

Aside from both being fantasy/romance/mystery, both gave me similar vibes, but they do have some differences.

Similarities:
- Both are Fantasy/romance/mystery dramas, with more mystery in the beginning and more romance towards the end
- Both have creepy fantasy elements and involve heavy emotions/decisions which gives them a similar vibe at times
- Both involve a non-human character
- Both dramas involve a main character looking for their parents/parent
- Both involve exploration of afterlife, gods, and have similar depictions of the journey to death (on a boat in a river)
- Both dramas involve quite a bit of saving

Differences:
- While TOTNT has some historical backstory, it is set in modern time and Arang is set in Joseon time
- Arang involves more slow burn romance where TOTNT the main characters fall in love much more quickly
- While Arang also has fun side characters, it feels much more contained/focused on the main characters while TOTNT has more of an ensemble cast feel

I would recommend these dramas if you think the similarities are why you liked one or the other drama, but if the things that are different between the dramas made you like one or the other drama, I would be hesitant to recommend it.