Why does air-gapped environment require rolling your own CI/CD solution? Plenty of examples of air-gapped Jenkins and/or Argo Workflows. Was this just an educational exercise?
It seems like a simple CI/CD in an airgapped environment might be simpler to implement than to (1) learn and (2) onboard an off-the-shelf solution when your airgapped requirement limits your ability to leverage the off-the-shelf ecosystem.