I would first like to say that I do not condone actual or real-life yandere violence (such as kidnapping or assault), I just enjoy these in fiction.

 I'm looking for any dramas (or movies) that have a  "soft yandere" lead, as in an extremely possessive person who melts around their love interest and wouldn't be brutal with them, just desiring their affections and closeness. They can be violent toward others though and I'm a-okay with any gore and violence.


Lady & Liar: ML is really gentle around the FL, but he does a lot without her knowledge to ensure their relationship lasts (he also lied to her about her identity so that she would stay with him)

The King's Woman: ML initially forces the FL to be with him, but he shows her that he cares about her (by hiding his other plans from her, especially related to the SML)

Kono Otoko wa Jinsei Saidai no Ayamachidesu: ML is a strange stalker who is willing to do anything to obtain the FL's love (such as being her puppy)

Extra:

Missing You: SML is a murderer (the villain) who acts as a loving husband to the FL but secretly plots the ML's demise (SML has a considerable amount of screen time because he plays two roles)

I think Moon Lovers: Scarlet Heart Ryeo may fit!

Seijo  FL goes full yandere mode at the end of the show. Not a happy ending  
Bonus: Older Woman/Younger Man


It's Okay to Not Be Okay  Very possessive FL

I have a list you might be interested in : Obsessive/possessive/clingy or yandere guys in dramas/movies

This has descriptions of what kind of guy each drama has,  hope it helps