What? A useful tool for the Admin user? :| Sorry ... none of which am aware. Closest thing I've found is a moosh command but it doesn't go into any detail depth .... does course level totals.
Would make a nice 'feature request' but wouldn't think it would be a 'high priority' ... even if one had a $1Mil Moodle Association thang specifically for that.
You can imagine the background. Covid-19 has this delayed side-effect of swollen disks. So to "read the riot act" the Moodle admin needs evidence and suggestions how to save. Unfortunately this is going to be a) a repeated exercise b) done by many local Moodle administrators. Making a package is the only solution.
I remember that a whole series of plug-ins were written around the Moodle's repository concept and hoped there could be one with the said functionality.
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