I'm pretty sure this is an actual bug with GCP at the moment. I'm the Organization Admin for the GCP organization (I've quadruple checked this, and that I'm signed in with the correct account).
But when I go to Manage Resources, And try to create a new folder, it doesn't let me select the organization as the location, because I "don't have the required resourcemanager.folders.create permission". If I try to create the folder in a project that's in the organization, I get "Unknown error".
I'm the user who created the organization and all projects in the first place, and the only G-Suite user that even exists on this domain.