YAML isn't the problem. It's that every single action is basically curl-to-sudo-bash. Even disregarding the security implications, the ergonomics are truly horrendous. They were with Azure DevOps and they certainly are with GitHub Actions. Bad interfaces, surprising behavior, it's got it all.

CI must only consist of shell commands. No abstractions, no surprises. (Except maybe with PowerShell, where the principle of most surprise rules.)