While not directly stated, the main character is heavily coded to be autistic and some people treat her badly because of it. It is portrayed negatively though
In season 3 episode 3, there's a very brief shot of a puppet hanging from a rope in a haunted house ride in an amusement park. It's shown from a distance and in dim light. --- In episode 9, in one of the dollhouse rooms there's two small puppets hanging from the ceiling. --- episode 10, no unexpected scenes/shots though --- In season 4 episode 6, final scene, Henrik finds a hanged body in an empty house.
The most graphic and upsetting one is at the end of s3e5, where a character's body is shown after suicide. Another character kills themselves offscreen at the end of s3, and it is shown briefly in a flashback in s4. Main character's sister's suicide is discussed throughout the show.
Saga blames her self for Emil Larssons (perpetrator from season 3) suicide. She has not seen Emils suicide, but was told by her supervisor Lynn that he used a paperclip to commit suicide. When Sage picks up some paperclips she dropped on the floor, her brain conjures a vivid image of Emils suicide.