RAP : How do you model complex validations & error handling without breaking Fiori UX

Hello SAP Community, I would like to get guidance and best practices from the community and SAP experts. Project Context Technology: RAP (ABAP Cloud) UI: Fiori Elements (Object Page + List Report) Backend: S/4HANA Business Object with: Draft enabled Multiple child entities Complex business validations Real Problem Statement In our project, we have complex validations such as: Cross‑entity checks (header + items) Checks against existing records Conditional validations based on status, user role, or business rules We implemented validations using: RAP validation methods FAILED , REPORTED , and…