Create User Action Report

There's no one report that does this, but a journal entry report certainly comes close.

https://experienceleague.adobe.com/en/docs/workfront/using/reporting/reports/create-manage-reports/create-journal-entry-report

Other than this, it will depend on what you consider a reportable action. When we audit our users for deletion, we try and make sure they have zero footprint. For us this means they didn't upload a file, submit a request, make a comment, or get assigned to anything. So we run four reports, and if they all come up empty, we delete the user.