'Google Workspace Business Starter’. Using a service account that impersonates a user in space where service account is not a member

In a Google Workspace Business Starter edition.

If I use a service account that impersonates a user,can I create a message in a chat space thathas the impersonated user as a member while the service account is NOT a member?

The service account email is considered "external to organization" and not admitted as member of a "chat space" in GWB Starter edition.

Asyncronous app using python (server to server):

    scopes = ['https://www.googleapis.com/auth/chat.bot']    credentials = google.oauth2.service_account.Credentials.from_service_account_file(        service_secret_file_path,        scopes=scopes)    delegated_credentials = credentials.with_subject(email)

service.spaces().messages().create().execute() return:

invalid_scope: Some requested scopes cannot be shown: [https://www.googleapis.com/auth/chat.bot]

Is this the symptom that a service account, although domain wide delegated and representing a user who is a member of the space, is not valid?