default or selected kernelversion does not have config value CONFIG_DRM_RADEON_UMS.
Result is shown for kernelversion 6.5.1

Enable userspace modesetting on radeon (DEPRECATED)


Linux Kernel Configuration
└─>Device Drivers
└─>Graphics support
└─>Enable userspace modesetting on radeon (DEPRECATED)
In linux kernel since version 3.1 (release Date: 2011-10-24)  
Choose this option if you still need userspace modesetting.

Userspace modesetting is deprecated for quite some time now, so
enable this only if you have ancient versions of the DDX drivers.