George Martin gave an in-depth interview to The Hollywood Reporter, which provides information about the books and their screen adaptations. The writer screenwriter seems to be considering finishing "A Song of Ice and Fire."
George Martin wrote... the script for "The Knight of the Seven Kingdoms" and sketched out a dozen more stories about Dunk and Egg for TV
But don't expect any rose-tinted happy endings like in the Game of Thrones series finale: Martin is thirsty for blood.
I was going to kill more people. Not the ones who were killed [in the series]. They made the ending happier. I don't see a happy ending for Tyrion. His whole story has been tragic from the beginning. I was going to kill Sansa, but she's so appealing in the series, maybe I'll let her live...
However, what are "Dreams of Spring" when "Winds of Winter" is still unfinished? Besides, to write books, you first need to take a break from television.
And from the same source, some interesting information has emerged about the prequel about Aegon I Targaryen: "HBO is developing this project as a possible drama series, and the Warner Bros. film team is developing it as a powerful feature film, comparable in scale to Dune."