You have been using the Neo4j graph database. Why not a relational database?
The relationships I described above already involve a few different types of connection between things. Once you start mapping dependencies between systems, connections to infrastructure etc., you end up with thousands of records, all connected in an ever-growing variety of ways. Neo4j scales well to this in two different ways; firstly, it’s schema-less, so the model can easily grow to represent things we haven’t considered yet, and secondly, querying highly connected data is more intuitive and performant using a database that is optimised for graph data.