Authorization for Google Identity Groups

Hello, the new google-beta version 3.29.0 has support for the new resource google_cloud_identity_group but I can’t figure out how to authorizse. According to the documentation (

I have to use domain wide delegation.I want to manage groups on GCP organisation level using the same domain as I have in G Suite Business. I use a service account in terraform with domain wide delegation enabled and “Identity Platform Admin” role assigned. Normally we need to use a gsuite account with Gsuite admin roles to impersonate when using GSuite APIs but I can’t specify an email address in the resource

Does anyone have an idea what I might be doing wrong?