I am not going to answer your question, but...
The "normal" procedure for controlling LEDs is not by changing the default configuration using "uci". All controllable LEDs should be accessible at "/sys/class/leds"; you can just read and write from those "files".
If you share your code others can have a look at it, and point where could be the issue.
If you are willing to enter the rabbit hole, search for these terms, and keep yourself entertained for an evening or two: HomeAssistan, Domoticz, Tasmota, ESPHome, OpenHAB, Arduino, ESP8266, ESP32, firmata, ...