Things I cannot get to work in LuCI

most Raspberry use Broadcom WiFi chips and these Broadcom Wifi drivers are kind of limited.

e.g. no WPA3 on RPi and some (or all?) RPi cannot work as repeater: Raspberry Pi Zero W: WiFi client mode not working - #10

It could be that the limitation that you are experiencing is due to yet another Raspberry Broadcom driver limitation.