On https://performantlabs.com/automated-testing-kit/installation the path to atk_setup is web/modules/contrib/automated_testing_kit/scripts/atk_setup. That is not correct.
Try to run the script as documented.
Unless to location of atk_setup is moving from https://git.drupalcode.org/project/automated_testing_kit/-/blob/1.0.x/mo..., the documentation should be updated to `web/modules/contrib/automated_testing_kit/module_support/atk_setup`
With that path, I get `Install Cypress or Playwright and run this from the project root.` in DDEV... so I'm guessing I'm still missing a step in https://performantlabs.com/automated-testing-kit/requirements, but I'll open another issue about that when I figure it out.
Fixed
1.0
Documentation