Hi Sam,
You are correct, Cerner has not exposed a create interaction for Account resources at this time. We are actively developing new R4 APIs, so I would encourage you to continue monitoring this group and
fhir.cerner.com to watch for new capabilities that are added to the server. Unfortunately, per group guidelines, I cannot share any information on future timelines for specific resource interactions.
In the current state, Cerner engineering can assist you in staging data that will be valuable for your development and testing. Please feel free to request specific information to be created via this group and we can build it out for you.
Thanks,
Max (Cerner)