looking for kdramas about loneliness

hello everyone! im looking for some kdramas that explore the theme loneliness. i want to watch ones that highlight this theme through portraying characters that experienced the loss of a loved one, emotionally stressful challenges, heartbreak, loss of identity, or abandonment. i like watching dramas that focus on character development, depicting the characters feelings and challenges, and what they need to go through to solve them, if that makes sense.

a show that i recently watched that presented this theme well was its okay not to be okay, i really like how this drama portrayed loneliness caused by past events/trauma in the characters lives, and how it affects their relationships with other people. this drama also had alot of emotional intensity/inner depth which i really enjoyed.

dramas ive already watched:

true beauty, find me if you can, descendance of the sun, extraordinary you, at a distance spring is green, my liberation notes, squid game, hometown cha, your playlist, at eighteen, move to heaven, business proposal, boys over flowers