I am trying to create a custom role with some course admin privileges (specifically managing backups), but not the right to updating course settings.

I have started by creating a custom role "Backup manager" with archetype Guest and additional permissions:

View courses without participation (moodle/course:view)

Backup courses (moodle/backup:backupcourse)

These options are available in the course admin menus when using the Classic theme, but do not appear when using the Boost theme, unless I also add the permission:

Update course settings (moodle/course:update)