default or selected kernelversion does not have config value CONFIG_NF_NAT_MASQUERADE_IPV4.
Result is shown for kernelversion 6.9.2

CONFIG_NF_NAT_MASQUERADE_IPV4 (not configurable)

configname: CONFIG_NF_NAT_MASQUERADE_IPV4

Linux Kernel Configuration
└─>Networking support
└─>Networking options
└─>Network packet filtering framework (Netfilter)
└─>IP: Netfilter Configuration
└─>NF_NAT_MASQUERADE_IPV4
In linux kernel since version 3.10 (release Date: 2013-06-30)