And season 6 is arguably the best season and it wasn't based on his books.
You keep saying this like every five pages but the overall structure of season 6 is either based on the books or based on what everyone knows is going to happen in the books.
Jon being resurrected is something everyone knows is going to happen.
The battle for Winterfell is a battle that is being set up in the books.
Recruiting northern lords to fight the Boltons is based on the books.
The battle for Mereen is a battle that is being set up in the books.
Jon being declared king is being set up in the books.
Ramsay writing a threatening letter to Jon is based on the books.
Arya being blind and having to get her sight back is based on the books.
Arya being with the theater troupe and being assigned to kill folks is based on the books.
Jaimie going to the riverlands to lift the siege is based on the books.
Cersei blowing up shyt with wildfire is based on the books.
Freys being baked into pies is based on the books.
Bran being in a cave with the three-eyed raven is based on the books.
The Tower of Joy battle is based on the books.
The kingsmoot and Greyjoy division is based on the books.
The Hound being alive and at peace is based on the books.
It wasn't like they created wholly original plots for season 6, they just moved some events around, combined characters, stuck a few main guys in already existing plots, confirmed commonly held theories, streamlined more complicated stories, embellished some other stories, and filled in a few gaps.
The show only original shyt, like Arya getting poked up, the Sand Snakes killing Doran and Tristian and taking over Dorne with no one caring, Tyrion making awful jokes for an entire season while struggling to run Mereen, Sansa withholding key information from Jon yet somehow coming out of it as a "master player", Ramsay killing Roose and Walda so brazenly with no one caring, are arguably the worst parts of a mostly great season.
And imo, the jury is still out on how they revealed the origins of the White Walkers.
There were some great original moments, like Hodor (as much as it can be called original since GRRM told them it happens in a future book, albeit in a different way), Sam going to Hornhill, and some of the Tommen, Margaery, Jaimie, Cersei, Olenna, High Sparrow moments. But the skeleton of season 6 was book shyt.
And I noticed people bring up hardhome as something "not in the books" too, when that was also an event that happened in the books. Jon just wasn't there. But they mention that something awful happened at Hardhome. The showrunners just decided they needed a big battle, so why not go there and show what happened. Filming something for the show that occurs off page in the book is not coming up with original material. That would be like saying Ramsay torturing Theon isn't based on the books because we don't see any of it on the page.