I'm not sure I follow, here's an example `pipx run` script:

  #!/usr/bin/env -S pipx run
  # /// script
  # dependencies = [
  #   "click==8.*",
  #   "Jinja2==3.*",
  #   "tomli==2.*",
  # ]
  # requires-python = ">=3.8"
  # ///

And it does manage temporary environments.