Welcome, @jtdo
You can purge users under the Admin section of the application interface. That will mark all of their data as deleted and remove the account, then the cleanup script will find the deleted data and remove it. If you enable GFPR mode, that old account email address will be stripped as anonymous, too, allowing the email address to be reused, or at least “forgotten”.
And you can consider using this utility, too, even creating a custom process that does exactly what you want to do, in a batch. → GitHub - galaxyproject/gxadmin: Handy command line utility for Galaxy administrators 🚀
We have resources here that you will find useful, too!
You might also be interested in the Admin chat group. Please see the Systems workflow group here for a join link and related resources. → Galaxy Working Groups - Galaxy Community Hub
Hope this helps! 