Your files, assignments, grades, discussions and other core Canvas features are stored. But the content hosted on external websites or platforms, One Drive, Google Drive or YouTube, are not stored on Canvas.
Note that students can also access all their Canvas courses during their study in the Academy. If you have created assessment, i.e. Quizzes, on Canvas that you do view after completing the course, you can “unpublish” the assessments.
You can access all your Canvas courses, past and present, during your time in the Academy.