Those are not avaiable for offline download (eq. as pdf etc.); you can use them only online (don´t know if they will be avaiable offline in the future):
If you use Galaxy: Extras -> Online-Extras: Art-Booklet // Digital Comic
or
access your library by browser: there are the same links for both; you can find the links by clicking on "Download Offline Backup Game Installers". After that, just scroll down.
When getting to the websites for booklet & comic, you have to logon with your Gog account.
Hope, this helps.
P.S.: please kindly use for futher questions/discussions the cp fourm:
https://www.gog.com/forum/cyberpunk_2077#1608027264