@Edent @neil @kenogo
On #Linux, use #Calibre with two plugins. #DeACSM emulates ADE so you don't have to run that. #DeDRM will remove most DRM in conjunction with DeACSM.

Easy to set up, I've used this combo for a few years. Links:
DeACSM - http://plugins.calibre-ebook.com
DeDRM - https://github.com/noDRM/DeDRM_tools
Calibre - https://calibre-ebook.com