As I said, I wanted to recreate them all anyway, so deleting everything is not a problem.
My keyboard is a Strafe RGB (MX silent), bought a few months ago and never had any problem before.
After reinstalling ICUE and creating a new profile (with no action in the library), the issue came back and I can't remap the keyboard :
An action that remaps the escape key (tried with and without retaining original key output) doesn't fix the problem at all.