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

Single queue writeback throttling

configname: CONFIG_BLK_WBT_SQ

Linux Kernel Configuration
└─>Enable the block layer
└─>Single queue writeback throttling
In linux kernel since version 4.1 (release Date: 2015-06-21)  
Enable writeback throttling by default on legacy single queue devices