https://www.gamespot.com/articles/why-shadow-of-war-takes-liberties-with-lord-of-the/1100-6453821/

Like its predecessor, Middle-earth: Shadow of War tells an original story set in the Lord of the Rings universe. As such, it bends the established canon, doing things like presenting the spider Shelob as a human woman.

While you can check our our Shadow of War review for thoughts on how it's turned out, we recently discussed the challenges of making a Lord of the Rings video game with Tony Elias, Monolith's lead narrative designer. In our chat, he touches on why it wouldn't be fun to do a straight adaptation of the books, the rationale behind Lady Shelob, and whether he would be interested in taking on the material in The Silmarillion.