default or selected kernelversion does not have config value CONFIG_EFI_GENERIC_STUB_INITRD_CMDLINE_LOADER.
Result is shown for kernelversion 6.9.9

Enable the command line initrd loader

configname: CONFIG_EFI_GENERIC_STUB_INITRD_CMDLINE_LOADER

Linux Kernel Configuration
└─>Device Drivers
└─>Firmware Drivers
└─>EFI (Extensible Firmware Interface) Support
└─>Enable the command line initrd loader
In linux kernel since version 4.14.326 (release Date: 2023-09-23)  
Select this config option to add support for the initrd= command
line parameter, allowing an initrd that resides on the same volume
as the kernel image to be loaded into memory.

This method is deprecated.