An approach with no overhead would be an Ad-hoc database query. The only input is the courseid. The output would be a table with columns: filename, filesize, author, date, context (course itself or the resource or activity the file belongs to).
The tricky part is to navigate the context path in contextid. See for an example https://docs.moodle.org/38/en/ad-hoc_contributed_reports#List_course_resources_accumulative_file_size_and_count.
If somebody is ready to take the challenge, you are very welcome! I am pretty sure there are other