FWIW, here is what I found when trying to set Ctrl+Alt+E to any calibre action on any calibre version:
CCR Shortcuts tab info:
Code:
Create catalog Create catalog None Ctrl+Alt+°
It does NOT map to Ctrl + Alt + E on my laptop, for some reason!

It maps to Ctrl +Alt +Degree Symbol.
Hence, it doesn't work... Yet Ctrl + 4 is tested working on every EBD action.