After seeing the videos, I started to test some python codes to decrypt the book, or at least verify what was not used.
Therefore I created some python scripts to parse and test some algorithms on Repl.it, which I think is quite useful.
The validation is a simple algorithm that can validate the answer using a dictionary, but I implemented using the Wikipedia validation.
The results I have so far, show that the pages did not use cryptography atbash with any cryptography key.
First program implemented ~ code
With this program we were able to prove that the first 4 pages and the last page is not using Arbaat ~ with swift [-28 to 28].
Done: Arbaat verification from -28 to28.
Doing: Implementing now the backward verification [done]
What is missing: the only possibility is to use Arbaat with anagram words
Result: atbash was not used on those pages