Centralized user management experience: Provide access permission to portal-only-customers page in admin hub for UAA role

Request to provide and/or ensure that the user-access-admin and site-admin roles have access to the portal-only-customers page (per JSM product/site; at a site level) under the new centralized user management experience in the admin hub.
Under the old experience, site-admins had access to the page but it appears that both the UAA and Site-Admin roles under the new experience can't access the page.