default or selected kernelversion does not have config value CONFIG_8723AU_AP_MODE.
Result is shown for kernelversion 6.4.14

Realtek RTL8723AU AP mode

configname: CONFIG_8723AU_AP_MODE

Linux Kernel Configuration
└─>Device Drivers
└─>Staging drivers
└─>Realtek RTL8723AU AP mode
In linux kernel since version 3.15 (release Date: 2014-06-08)  
This option enables Access Point mode. Unless you know that your system
will never be used as an AP, or the target system has limited memory,
"Y" should be selected.