Go with Node.js and use a framework. I can recommend NestJS or Fastifiy as a Backend Framework. They both have a strong community and Fastify is the successor of Express but much faster.
I would say, it depends a bit on your use case.
I use Flask to expose REST endpoints which then can be consumed by the frontend. However, if you need a full-stack then go for Django.
In my opinion, Flask is much easier but Django comes with everything.
Try out cookiecutter for Django to have an easier start
https://github.com/pydanny/cookiecutter-django
You could also use AWS Lambda and use Cloudwatch event schedule if you know when the function should be triggered. The benefit is that you could use any language and use the respective database client.
But if you orchestrate ETLs then it makes sense to use Apache Airflow. This requires Python knowledge.
