How to turn on night light only for a specific monitor in a dual-screen setup

I am using Ubuntu 20.04.02. I have connected an old LG monitor via an HDMI cable. When I turn on the Night light- both the monitors (laptop screen and old LG monitor) are affected (as they should ideally).

Is there a way to only use the night light on the original screen(laptop) and view the old screen(LG) as it is without the night light?

Edit: I am using the "Join Display" feature.

In fact, I was also trying to do the same thing for my external monitor. Here is what I have done.

First open your terminal and list the connected devices using xrandr (if xrandr is not installed, then you might want to install it).

    xrandr -q | grep " connected"

Here you might see the list of connected devices as:

    HDMI-0 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 476mm x 267mm
    eDP-1-1 connected 1920x1080+0+1080 (normal left inverted right x axis y axis) 344mm x 193mm

HDMI-0 is my external monitor. I wanted to turn on night light in this monitor so I altered the value of RGB via --gamma flag as:

    xrandr --output HDMI-0 --gamma 1.1:0.8:0.7

You might also want to alter the brightness of the monitor. You can do that by via --brightness flag as:

    xrandr --output HDMI-0 --gamma 1.1:0.8:0.7 --brightness 0.55