Error rendering Jinja template for Airflow task using BigQueryOperator with SQL file containing template fields

Question

I'm encountering an issue with an Airflow DAG task utilizing the BigQueryOperator. The task involves executing a SQL file (cast.sql) stored at "/home/airflow/gcs/dags/movies/sql/RRR/", and I'm passing parameters to the SQL file using the params argument in the BigQueryOperator.

sql_path = "/home/airflow/gcs/dags/movies/sql/RRR/cast.sql"

stage_latest_parameters = {
    "project_id": project_id,
    "dataset_name": dataset_name,
    "date": raw_latest_date,
    "source_table": source,
    "dest_table": dest
}

sql_with_parameters_task = BigQueryOperator(
    task_id='sql_with_parameters_task',
    sql=sql_path,
    params=stage_latest_parameters,
    use_legacy_sql=False,
    dag=dag
)

ERROR:

 Exception rendering Jinja template for task 'sql_with_parameters_task', field 'sql'. 
 Template: '/home/airflow/gcs/dags/movies/sql/RRR/cast.sql'
  ...
 jinja2.exceptions.TemplateNotFound: /home/airflow/gcs/dags/movies/sql/RRR/cast.sql

QUERY:

  CREATE OR REPLACE TABLE `{project_id}.{dataset_name}.{dest_table}` 
  AS
  SELECT *, {date} AS date
  FROM `{project_id}.{dataset_name}.{source_table}`

Here, I don't need to use any templates. I just need to run the query by passing necessary parameters that are sitting inside a GCS bucket. What was I doing wrong? Appreciate your Help.