What curse does Harry Potter's son Albus S. Potter have and why?

Read the book.

Honestly, this question isn't as straight forward as it seems. The script/play never clarifies who the cursed child is. I think it could be any of these characters, if not all of them in their own way:
Albus Serverus Potter- born to Harry Potter, who's name is known across nations, who defeated Voldemort himself, feels as if he has so much to live up to. From being sorted into Slytherin, (yes, Harry Potter's son), and failing to impress in Quidditch and more his parentage really is a curse for him as he feels as if he constantly has to live up to his father's image.
Scorpius Malfoy- is also a victim of his parentage. His father Draco Malfoy was a known Death Eater and tried to cloud is family in secrecy so that the public would forget about them. But Scorpius, despite being smart, kind and loyal, was constantly judged for his parentage and his parentage was even questioned. People thought he was really the son of Voldemort.
Delphini, or Delphi for short could also be the cursed child, and also because of her parentage. Delphi was a very versatile and powerful witch and if her parents weren't Voldemort himself and Bellatrix Lestrange and if she wasn't brought up in a world of dark magic she could have been a brilliant witch and could've accomplished much.