You highlighted my issues with the series. Most of the characters are just too two-dimensional. Sometimes the depth they're supposed to show through their developlment is lacking. Also, the show proves that chess is simply boring on the screen unless you're a master player who knows everything about the game.
I guess, poker could be the same for those who haven't got a clue about it, but still, Rounders is just more exciting than any movie ever made about poker players. Why? Because the characters are genuine and keep the audience engaged. The Queen's Gambit sometimes gets its head way too deep in the chessboard and forgets that most of us are here for the characters and the drama.
Nevertheless, it's an inventive and entertaining show.