@FlemmingVesterg If you are using SIS Import CSVs, the status column in the courses.csv file determines whether courses are created as unpublished or published. The status 'active' should create courses in the unpublished state, but the status 'published' would create them in the published state. If your SIS creates the CSVs already formatted for Canvas import, you could edit the status column values.

If you are using a different means of importing course information from your SIS, please share more details.