I have set up a minimal version of a Composer environment in GCP. Through Terraform, I have deployed this thus far:

resource "google_composer_environment" "airflow-poc-env" {
  name = "airflow-poc-environment"
  region = var.region

  config {

    software_config {
      image_version = "composer-2.8.4-airflow-2.7.3"

      env_variables = {
        DWH_PROJECT="VALUE"
      }
    }

    node_config {
      service_account = module.cloud-composer-service-account.service_account.email
    }

  }
}

Now, I want to give the Airflow environment certain variables that I can use when defining a task within a DAG, e.g.

start_cloud_run_job = CloudRunExecuteJobOperator(
        task_id='<task-id>',
        region='<region>',
        project_id=Variable.get("DWH_PROJECT"),
        job_name='<job-name>',
)

As provided in the Terraform documentation, I suppose that the env_variables block should provide key-value pairs of variables in the Admin > Variables section in the Airflow UI. Or is this not the case and should you always provide those variables manually? Below the section I mean.

Airflow Variables section

I tried to provide key-value pairs within in the Terraform config, expecting that this will deploy environment variables in the section above.
Or maybe another question: can those environment variables be set via Terraform or should you provide them manually or via the Variable.set(key="DWH_PROJECT", value="VALUE", serialize_json=<bool>)?