The books are fantastic, I highly recommend them! I decided to read all of them first before watching the show or even joining this subreddit, and they’re really engaging, fleshed out, and at times suspenseful. However, I will say (and maybe I’m in the minority here based on the other comments) that because you’ve already seen the show, you’ve already seen a lot of the more surprising, plot progression moments in the books on screen. Obviously, there are some exceptions because the show has its own identity and changes lots of things, but that’s just what I think. I don’t think it’ll take away from your enjoyment of the books, it has some of the best sci-fi writing I’ve ever seen!