Ouch. That sounds terrible with or without YAML anchors. GitHub Actions has overall been a great addition, allowing projects to integrate CI directly into their PR process. But, I never understood why it didn't have simpler paths for the very common use cases of CI and CD. Virtually any other dedicated CI product is considerably easier to bootstrap.
:) :) :)
.github/workflows in my current project: 33 files, 3913 lines total, 1588 lines unique.
(and this was _after_ we moved all we can into custom actions and sub-workflows)