Summertime

Similar as to the high school setting and the plot where two boys who grew up together explore romantic feelings and sexual tension.

Short korean boys love dramas taking place in high school about two guys who have known each other and have been friends since forever navigating and confronting love and feelings as a third person comes to threaten what they have
moments of jealousy and anger
Summertime seems to be alot darker than WYEL, though, and feature more ... kisses etc

Similar air of obsession and possessiveness, thanks to a lead character who comes off as dangerously unhinged.

Both are korean boys love dramas produced by OAK Studio with an obsessive and very proactive male lead.
-freaky and sexual content in both
- both are adapted from novels so if you want to dive deeper into the worlds of these characters you can read those

Both are korean boys love dramas produced by Studio OAK with an obsessive, possessive and dominant male lead
Characters longing for somebody with an intense desire and seeking a relationship beyond just "friends" or "cousins"

- Childhood friends to lovers with (more than) a pinch of obsession on one side.
- One lead actively drives away others to stay the second lead's number one
- Height difference
- A good bit of banter between the leads

Forewarning to check Secret Lover's tags if you are sensitive to any TWs!
The leads in Secret Lover are, thus far, a lot more "friendly" (Dohyeon [in Summertime] comes across as a bit more "cold" in nature).
Secret Lover has some fake dating trope moments briefly where as Summertime does not.