Being able to receive a list of 3 similar courses that you've completed will help elevate the engagement and visibility of courses. Users typically doesn't have the time or energy to search for a related course.
It would also be helpful to know if there are additional courses to dive deeper on a particular subject.
Could you use the "Enable Recommended Courses" option, which you will find in the 'Catalog Visibility' section when adding a course? When you turn it on, you select which tag you want. For example, if you select the tag "Leadership" and they've just completed a course that's about leadership, they'll then see recommended courses that relate to that topic.