What Ontology, RAG and Graph data do you use to develop Intelligent Assistants?

I want to use RAG for a complicated product consisting of maybe 100 different systems interacting with each other in many different ways. We have an Archimate model describing these relations including both the structural and behavioral relations between these systems and relations to their related business processes and business users.

We want the support people to use the rag solution when problems occurs to trace the errors and to be able to inform the correct business users which processes are affected.