Nutanix Objects does not use minio in the core data path. The presence of a binary in a kubernetes pod doesn't necessarily mean that the binary is being used or the fact that nutanix objects is nothing but a wrapper over minio. Earlier implementations did use minio purely as a S3 protocol adapter, i.e a protocol translator from S3 API to Nutanix internal storage protocol. This was something that was publicly acknowledged : https://blocksandfiles.com/2019/11/07/nutanix-objects-storag...
However, in later releases they seemed to have replaced the minio based protocol adapter to something that they developed in-house in C++ and have no longer using minio in their protocol stack.