Service blueprint
Three layers (customer, frontstage, backstage) divided by interaction and visibility lines. Built for finding gaps between what the system does and what the customer experiences.
Pick this when your story is about how the system shapes the experience: handoffs, gaps, who does what behind the scenes. Audience: leadership, partner teams, anyone who can change how it works.
Sarah Gibbons, "Service Blueprints: Definition," Nielsen Norman Group, 2017.