KubernetesPodOperator  pod_template_file content doesn't support jinja airflow template variables. pod_template_file  is part of templated_fields list. 
https://github.com/apache/airflow/blob/master/airflow/providers/cncf/kubernetes/operators/kubernetes_pod.py#L165

template_fields: Iterable[str] = (        'image',        'cmds',        'arguments',        'env_vars',        'labels',        'config_file',        'pod_template_file',    )

But pod_template_file content is not supporting template variables. pod_template_file can be implemented the way SparkKubernetesOperator implemented using template_ext

https://github.com/apache/airflow/blob/master/airflow/providers/cncf/kubernetes/operators/spark_kubernetes.py#L46
 template_ext = ('yaml', 'yml', 'json')
airflow/providers/cncf/kubernetes/operators/kubernetes_pod.py
"""
        Generate labels for the pod to track the pod in case of Operator crash
        :param context: task context provided by airflow DAG
        :return: dict
        """
        labels = {
            'dag_id': context['dag'].dag_id,
            'task_id': context['task'].task_id,
            'execution_date': context['ts'],
            'try_number': context['ti'].try_number,
        }
        
        if context['dag'].is_subdag:
            labels['parent_dag_id'] = context['dag'].parent_dag.dag_id
        
        
        for label_id, label in labels.items():
            safe_label = pod_generator.make_safe_label_value(str(label))
            labels[label_id] = safe_label
        return labels
    def execute(self, context) -> Optional[str]: