Ask HN: Which CI/CD do you use for a monorepo?

I am looking or the simplest (ideally YAML free) CI/CD that uses either Dockerfiles, worse YAML files to trigger builds.

I would like to place a file to a folder that has specific instructions how to build the projects.

Example:

- repo/backend/api

- repo/frontend/www

- repo/frontend/app

I would like to have 3 files that define how each folder builds. Api might be Python and deployed to arm64, www is static html, css, etc. deployed to a CDN.

I do not understand why the major CI/CD vendors have a convoluted YAML hell with custom images and commands when we have Docker for 10 years. In last 10 years non-of the CI/CD vendors I know of created a platform where I can use a Dockerfile that references a public or private image that I can use to build my project. At this stage I am only AWS Codebuild that allows the use of Docker image from ECR but I still need to do YAML.

Is there a company that has a super simple CI/CD that would be 5 minutes to set up?

We have wasted couple of weeks on CircleCI and whenever we need to change it is a major pain and it takes hours to find out which YAML line has an incorrect indentation or why a certain tool breaks when used on a "orb".

I am just getting tired of these.