Q: How can I remove ability to request backfills from the Hiring Manager role?

A: We don't recommend removing the ability. You want your managers to be able to request backfills.

However, in certain circumstances, it may make sense. Granular permissions of requesting one type of headcount versus the other isn't part of the permission set right now. You can disable 'Rqeuest new headcount' permission from the Hiring Manager role, as shown below.