The type of CI you're describing would be in the "simple" category in the OP - if your goal is just "run a single docker build and check if it fails" there are

The type of CI you're describing would be in the "simple" category in the OP - if your goal is just "run a single docker build and check if it fails" there are lots of free hosted tools you can set up (github actions, gitlab CI, etc) There is in fact a burgeoning industry of devops consultants that set up CI pipelines for companies, I'd encourage you to consider it if you like the work!