If I’m understanding you correctly, perhaps we just simply disagree on the role of the Catholic Church. I do not believe for a moment that the Catholic Church confuses anyone with the term “mortal sin”.
But what has confused a great many Catholics, and in my view is largely responsible for the unchecked immorality sweeping across the world, is the Protestant concept of “let your conscience be your guide” that you are suggesting. Unlike the worldly-influenced subjective beliefs of the conscience, mortal sin is a well-defined objective standard that has faithfully guide for millenniums.
I would never disobey Church’s teachings. Nor do I think you would.
So what is your understandng of Church’s teaching on mortal sin?
On conscience?