I'm able to remove and re-add them to the gravity.db, but my problem is that this doesn't remove them from the Admin Dashboard, which I thought was the whole point of the Audit button, right?
No, it's not. The purpose of the audit button is to remove the domain from the audit log. This tool is designed to present "new" domains. For every domain shown here you can say if you want to black/whitelist or just acknowledge that non of these action is required but the domain should not be presented again ("audit"). After you clicked on "audit" it's removed from the audit log - if you went through all domains in that log it will be empty until your Pi-hole sees a new non-audited domain. You can then decide what to do with the new domain.
Ah okay, sorry for the confusion and thanks for clearing that up. So just to confirm - there's no way to hide domains from the Dashboard, and it's not on the roadmap?