Reporting on licenses

I am looking to cleanup my enterprise account.  We have more than 23k licensed users.  I'm looking for a report or a way to compile multiple reports so that I can see which users have not logged in in more than 6 months.  Of those users, which do not have custom PMIs or cloud recordings.  If I can identify these folks, I can do a bulk import to either demote or delete their accounts to free up licenses.  Does anyone have any insight?  I do not find the reports available to us particularly useful or intuitive.