I've read them all, but that is thousands of pages and I don't necessarily remember every scene of carnage and death. As far as executions, there were beheadings, burning at the stake, flaying, and crucifixion that I recall. None of those were anywhere near as graphically described as they are shown in the series.
Somewhere in the last season or two, they reached the end of the material they had in the books and are now writing their own story. It will be interesting to see if George R. R. Martin will use the story as told in the series as the basis for his next books or just let those go and let the story be told by the series instead. Frank Herbert made some changes in the
Dune books that he wrote after the first movie came out so the beings who piloted their space ships were like the contrived interpretation you saw in the movie instead of what you read in the earlier books. The story was lessened by that concession to the movie in my opinion. But that was long ago and far away!