Harry Potter and the Cursed Child is a book/play about Harry's son. In case you're confused, it says "parts one and two" because it's two plays.
The characters are angsty and melodramatic. The book/play adaptation is a bit awkward. The plot doesn't make any sense. The writing leaves something to be desired. So, it's not a masterpiece.
HOWEVER, I read the play in the context of dramatic readings with my coworkers for an hour each Friday after work. We used funny voices and accents. We gave characters weird names and pronunciations (every session, Ginny had a different pronunciation). We made sound effects. We acted out the occasional dance move. And in that context, having a hokey, nonsensical, melodramatic play is great.
So I would encourage everyone not to take the play too seriously. Find a group of friends and have fun with it!