Bulk rename/append name of devices

Everything I need to do is at scale, so it's all got to be accessible programmatically.  Some systems pulled in with incorrect information, so I'm trying to correct them. (it's correct information, but not the info we need in that location for the way we use monitoring).  Our SQL clusters, due to the fact that we're a multi-tenant MSP, have several IP addresses, all associated with their own DNS entry.  Since they all came from the same source, most of them didn't map to the correct DNS name correctly due to how LM is grabbing its initial info during discovery.  So I've got to A) remap the existing, incorrect devices and B) Prepare for any future devices being added that may encounter the same problem.  Since adding a new tenant will add between a dozen and hundreds of servers, I'd rather not have to sift through them manually in the future, so fully automated is my preferred option.

Is there a specific reason that the displayname is inaccessible to the RESTAPI?  I assume I'm accessing it correctly as the other fields are changing correctly.