I finished "The Queen's Gambit" last week but haven't had time or energy to catch up on this thread. Lots of good comments so far! Just one thought to get it started again...
***Spoilers***
I think one reason maybe Heath was drawn to this story, besides being a chess freak, is that Beth is an orphan and a loner, very private, needing love but not expecting it, much like Ennis. Obviously, he knew something about that kind of character and felt he could bring something to the movie as its director. Qualities in Beth that remind me of Heath are her intelligence, strong will and ability to concentrate when it's necessary, her innate integrity and ability to size people up quickly and her dangerous fascination with drugs and alcohol.