I explain why you want to split user stories and provide some references on how to do it. After all, Epics are for customers, user stories are for the team.
user stories
What You Ought to Know about Writing User Stories
A set of resources about the key aspects of writing user stories. These are things people forget when they obsess about writing user stories “just right”.
How to describe user stories to build shared understanding
Some techniques you can use to describe user stories help you build shared understanding of your product and the outcomes you seek.