I work on a monorepo that does this using Typescript, for type checking. It's a mess. Huge learning curve for some type checking that very often will build perfectly fine but fail a type-check in CI.

Honestly, just having a linter should be enough. Ideally, anything complicated in your build should just be put into a script anyways - it minimizes the amount of lines in that massive YAML file and the potential for merge conflicts when making small changes.