True. I just installed Magisk and skipped the rest of the steps.This guide should be corrected somewhere.
Me, like other people, faced the same problem at step 13, before that all was fine.
Idk why, but i tried 2 times the entire procedure and got stuck in twrp reboot.
I tried using both Whale and Geoanto555 twrps but nothing changed.
After step 13 some error pop up and the phone is encrypted with a non-existing password.