Try running act against their own act fork and watch it vomit. I first had contact with act trying to get VSCodium to build locally, since their build system is/was entirely GitHub Actions based. The "well, that didn't work" was horrific to troubleshoot

  git clone https://gitea.com/gitea/act.git
  cd act
  make build
  ./dist/local/act -j lint -W .github/workflows/checks.yml --verbose  workflow_dispatch
  echo good luck