The following may be of interest. The New York Times has a GOT newsletter (which I only recently discovered, unfortunately) and this was in today's, a question from a viewer.
**
Do you know if David and Dan’s ending aligns with George R.R. Martin’s? Or have they gone their own way? — Liz Longley
So how much did George R.R. Martin have to do with the plot of Season 8? — Lisa Wrabek
Given that George R.R. Martin has yet to release the penultimate book of the series (“The Winds of Winter”), let alone the final one (“A Dream of Spring”), it’s hard to say precisely how he will close the story. Some of the major beats will likely be the same, but because of what Martin likes to refer to as the butterfly effect, it might also be remarkably different.
The books have a lot more room to develop complex plot and nuanced characters, and there are a great many characters who were culled in the TV series but still remain alive in the books, as well as many characters never introduced into the TV show at all. A major character who will play a role in Martin’s story is Aegon Targaryen. In the show, we’re told that’s the birth name of Jon Snow, Rhaegar Targaryen’s son with Lyanna Stark. But in the books, Aegon is the supposed surviving son of Rhaegar Targaryen and Elia Martell. So there is a potential for three Targaryen claimants to Iron Throne (including Dany and Jon), and the Aegon of the books is the one with Varys’s support. Already, you can see that it will be a bit more complicated than the TV version.
Martin has said that he provided an outline of his version to the showrunners in various story conferences years ago, with the goal to arrive at the same place, even if there are big differences with secondary characters. Martin didn’t read the scripts, though, and he didn’t see advance footage. If the show were completely true to his version, however, he has estimated that it would take five more seasons to get there. — Jennifer Vineyard
**
60 Minutes interview with George Martin.
https://www.cbsnews.com/video/will-...nes-books-end-like-the-hbo-series-60-minutes/
**
Rolling Stone interview with George Martin,
https://www.rollingstone.com/tv/tv-...rk-sisters-and-ending-game-of-thrones-813890/