I'm looking for examples of how others might have solved for this.
Did you build a custom cartridge?
Did you leverage some externally running agent to retrieve data by OCAPI (or Commerce Cloud APIs)? ...(i.e., a "pull" strategy)
I've read the documentation, spent many nights searching Google, searched the Salesforce Commerce Cloud Marketplace, spoken with several Salesforce Commerce Cloud expert consultants & system integration firms - but it appears no one is aware of anyone else doing this before.