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

Default message log level (1-7)


Linux Kernel Configuration
└─>printk and dmesg options
└─>Default message log level (1-7)
In linux kernel since version 2.6.39 (release Date: 2011-05-18)  
Default log level for printk statements with no specified priority.

This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
that are auditing their logs closely may want to set it to a lower