Currently no,
Since Competencies are awarded from the successful completion of a course activity the restriction should be placed on the course activity.
Kind Regards
Can you confirm it is not possible to restrict an activity using a learning plan status (100% etc)?
If yes, is there an extension to do so (I did not find any in the Moodle repo)? If not, would it be difficult to develop such a module and which one would be the closest to start from?
Sorry, I am not a developer. There may be a Moodle Tracker regarding this issue - you are not the first to inquire about this functionality.
Kind Regards