default or selected kernelversion does not have config value CONFIG_DISCONTIGMEM_MANUAL.
Result is shown for kernelversion 6.9.5

Discontiguous Memory


Memory model
└─>Discontiguous Memory
In linux kernel since version 2.6.13 (release Date: 2005-08-28)  
This option provides enhanced support for discontiguous
memory systems, over FLATMEM. These systems have holes
in their physical address spaces, and this option provides
more efficient handling of these holes. However, the vast
majority of hardware has quite flat address spaces, and
can have degraded performance from the extra overhead that
this option imposes.

Many NUMA configurations will have this as the only option.

If unsure, choose "Flat Memory" over this option.