default or selected kernelversion does not have config value CONFIG_BATMAN_ADV_SYSFS.
Result is shown for kernelversion 6.9.8

batman-adv sysfs entries

configname: CONFIG_BATMAN_ADV_SYSFS

Linux Kernel Configuration
└─>Networking support
└─>Networking options
└─>batman-adv sysfs entries
In linux kernel since version 5.1 (release Date: 2019-05-05)  
Say Y here if you want to enable batman-adv device configuration and
status interface through sysfs attributes. It is replaced by the
batadv generic netlink family but still used by various userspace
tools and scripts.

If unsure, say Y.