default or selected kernelversion does not have config value CONFIG_KASAN_S390_4_LEVEL_PAGING.
Result is shown for kernelversion 6.9.2

KASan: use 4-level paging


Linux Kernel Configuration
└─>Kernel hacking
└─>Memory Debugging
└─>KASan: use 4-level paging
In linux kernel since version 3.10 (release Date: 2013-06-30)  
Compiling the kernel with KASan disables automatic 3-level vs
4-level paging selection. 3-level paging is used by default (up
to 3TB of RAM with KASan enabled). This options allows to force
4-level paging instead.