The firm I work at developed an internal library (open source soon hopefully!) that does all our templating in Python, example:

  import os

  """
  Imports redacted, but this imports our library
  """

  NAME = "my_app"
  PORT = 5000
  DEPLOY_ENV = os.environ["DEPLOY_ENV"]

  deploy_all(
      create_stateful_service(
          NAME, http_port=PORT, cpu=2000, memory=500
      ),
      create_ingress(
          NAME,
          service_name=NAME,
          service_port=PORT,
          hostnames=["myapp.internal.com"],
      ),
  )

In the background, this converts a bunch of objects to YAML, leveraging the fact that objects in Python are just dictionaries. It then takes these objects and sends them to the K8S API. Really improved our DevEx since you can do complex tasks like "define a deployment, deploy it, and then check server status" because it is all just Python at the end of the day.

Edit: formatting