But I am considreing just failing the task.

This will of course work, just raise exception in the Task itself, and protect the call from the pipeline logic function with try/except

regrading the second option, try to nullify the hash on the Component Task:

# running the Task component here
# if we do not want someone to use us
Task.current_task()._set_runtime_properties({"pipeline_job_hash": None})