EDIT

I made a Nushell version of this script that is updated...
https://lemmy.world/post/48010802

I created a simple Bash script that will always disable the default/internal monitor on your laptop when using AR glasses (or any other external monitor). I find this useful for when using AR glasses such as the XReal One which allows you to change the mode from regular mode to ultra-wide mode and when doing this, it will act as your unplugging the XReal ones and plugging in XReal one again in a new mode, causing the interal laptop display to become enabled.

To keep the laptop display always off, weather the laptop lid is either closed or open, this simple bash script will always disable the laptop screen every X seconds (You can change it by changing the wait variable)

Simply copy this script and create a new bash script such as disable-display.sh, make the script file executable and add it to your startup applications and it will run in the background. You will need to run xrandr command with all of your displays enabled to get the names of the displays and change the variable names in the script accordingly.

NOTE: This script may not work with a full Wayland setup and may only work on X11.

Enjoy

#!/bin/bash

#RUN xrandr TO GET THE NAMES OF THE DISPLAYS AND SET THE VARIABLES TO THESE NAMES

readonly default_display="eDP"
readonly external_display="USB-C-0"

readonly wait=5

while true; do
    #Check if there is an external display connected
    if xrandr | grep -q "$external_display connected"; then
        #Disable the internal display
        xrandr --output $default_display --off
    fi

    sleep $wait
done