default or selected kernelversion does not have config value CONFIG_RPCSEC_GSS_KRB5_SIMPLIFIED.
Result is shown for kernelversion 6.7-rc3

CONFIG_RPCSEC_GSS_KRB5_SIMPLIFIED (not configurable)

configname: CONFIG_RPCSEC_GSS_KRB5_SIMPLIFIED

Linux Kernel Configuration
└─>File systems
└─>Network File Systems
└─>RPCSEC_GSS_KRB5_SIMPLIFIED
In linux kernel since version 6.3 (release Date: 2023-04-23)