default or selected kernelversion does not have config value CONFIG_RAMZSWAP_STATS.
Result is shown for kernelversion 5.4.229

Enable ramzswap stats

configname: CONFIG_RAMZSWAP_STATS

Linux Kernel Configuration
└─>Device Drivers
└─>Staging drivers
└─>Enable ramzswap stats
In linux kernel since version 2.6.33 (release Date: 2010-02-24)  
Enable statistics collection for ramzswap. This adds only a minimal
overhead. In unsure, say Y.