The Witcher 3's two DLC plots had nothing to do with the original novel.
Geralt's adventure unfolded in The Witcher 3: Wild Hunt, and Geralt's identity and background in the story was a profession called "Demon Hunter". They were responsible for destroying all kinds of monsters and magical creatures. The two main storyline characters," Demon Hunter " and " Blood and Wine," respectively described the different challenges Geralt and his friends faced in different situations. These challenges had nothing to do with the plot of the original novel.
In the storyline,"Demon Hunter", Geralt and his friends were forced to go to a place called "Dark Forest", which was full of mysterious magic and dangerous creatures. This area had nothing to do with the original plot, and the storyline "Blood and Wine" told the story of Geralt and his friends communicating with other wizards and monsters in the tavern. These stories had nothing to do with the original plot.
I think 'The Last Wish' is quite popular. It's often the starting point for many people getting into the Witcher series. The short stories are easy to digest and give a great overview of the world and its rules.
In a way, they are suitable. The graphic novels usually have engaging illustrations that can draw in beginners. However, they might not explain every single detail about the Witcher world. But still, the basic plotlines are there, and you can get to know Geralt's character, his adventures, and the general atmosphere of the Witcher world without having prior knowledge of the franchise.
Well, in Witcher 3 New Game Plus for swords, they can be more powerful. You could have already upgraded them in your first play and now they start off even better. Regarding the story, it's like reliving an old adventure but with a fresh pair of eyes. The choices you made before still matter and can lead to different outcomes this time around. It adds a whole new layer of depth to the gameplay and makes you feel like you're really part of the Witcher world all over again.
The Witcher novels have reached their conclusion. There are no more installments planned as of now. Fans have had the opportunity to experience the entire story arc as intended by the author.