I run ChromeOS 103 beta, no Developer access needed, and have figured out how to update Calibre so thought I would share.
I run linux (Debian Bullseye) within the ChromeOS container, and when Calibre requires sudo permission as root no password was set so you cannot go further.
The first time you run root@penguin in crosh you can set a password. If you want to run a script in Terminal requiring sudo permission within the container this is the password that is required.
Close Terminal and Calibre
Open crosh (Ctrl + Alt + t)
vsh termina (to open root)
lxc start penguin
lxc exec penguin -- bash (opens root@penguin)
passwd (enter new password twice)
sudo -v && wget -nv -O-
https://download.calibre-ebook.com/linux-installer.sh | sudo sh /dev/stdin
exit