Google OAuth: Invalid_client the oauth client was not found
Turns out there was a typo in my client id from using the up arrow (command history) on mac which wasn't visible until pressing enter and reviewing the command after execution.
Also found out that this scope (admin.directory) cannot be used with https://accounts.google.com/o/oauth2/device/code since devices are considered insecure, so only a limited set of scopes are allowed.