default or selected kernelversion does not have config value CONFIG_BLK_DEV_RAM_DAX.
Result is shown for kernelversion 6.7-rc3
Support Direct Access (DAX) to RAM block devices
configname: CONFIG_BLK_DEV_RAM_DAX
Linux Kernel Configuration
└─>Device Drivers
└─>Block devices
└─>Support Direct Access (DAX) to RAM block devices
In linux kernel since version 4 (release Date: 2015-04-12)
Support filesystems using DAX to access RAM block devices. This
avoids double-buffering data in the page cache before copying it
to the block device. Answering Y will slightly enlarge the kernel,
and will prevent RAM block device backing store memory from being
allocated from highmem (only a problem for highmem systems).
avoids double-buffering data in the page cache before copying it
to the block device. Answering Y will slightly enlarge the kernel,
and will prevent RAM block device backing store memory from being
allocated from highmem (only a problem for highmem systems).