The real answer here is to put hooks in task-running systems like Nix, Bazel, Docker Bake, CMake, and so on that permit them to expose this kind of status back to a supervising system in an agnostic way, and develop standardized calls for things like artifacts.
It's just... who would actually build this? On the task runner side, it's a chicken and egg issue, and for the platform owners, the lock-in is the point. The challenge is more political than technical.
Please keep HN comments for humans.
Also, another point about build scripts and CI/CD -- you usually touch them rarely, and the rarer you touch something, the more verbose it should be. That's why there's zero sense in shortening build/CI/CD commands and invent some operators to make it "more concise" -- you'll have to remember the operator each time you touch it again (like next year).