CONFIG_TIME_BOOTUP is not available for thedefaultarchitecture x86.
Result is shown for architecture v850
default or selected kernelversion does not have config value CONFIG_TIME_BOOTUP.
Result is shown for kernelversion 5.19-rc1

Time bootup

configname: CONFIG_TIME_BOOTUP

uClinux/v850 (w/o MMU) Kernel Configuration
└─>Processor type and features
└─>Time bootup
In linux kernel since version 2.6.21 (release Date: 2007-04-25)