However, we would like this app to be able to connect to multiple Neo4J instances. When a request comes into our controller, we would peel off the spring.data.neo4j.* values and use those to create a dynamic connection instead of using what's in application.properties.
Does anyone have any ideas on how to implement this or some examples?
A dynamic approach is not supported by Spring Data Neo4j. The same is valid for most of the Spring Data projects. SDN is not some kind of driver that can switch between instances very easily but needs some kind of guarantee that e.g. related data also ends up in the same database and does not create duplicates within different ones.