Scott in support found this version (R11-34) of QB Enterprise 2023 that fixed the issue. Uninstalled existing QB23, rebooted Server (2012 R2), loaded this version up and declined all offers to update. Unfortunately automatic updates can't be turned off. So it's working at the moment, but who knows for how long.

https://dlm2.download.intuit.com/akdlm/SBD/QuickBooks/2023/nctqf0a84US_R11/QuickBooksEnterprise23.ex...