// Set the scale of Laptop Display to 1920x1080 with a scaling of 1 (for use with Laptop open and 4K screen attached)
xrandr --output eDP-1-1 --mode 1920x1080 | gsettings set org.cinnamon.desktop.interface scaling-factor 1

// Set the scale of Laptop Display to 3840x2160 with a scaling of 2 (for use with Laptop in 4K Mode)
xrandr --output eDP-1-1 --mode 3840x2160 | gsettings set org.cinnamon.desktop.interface scaling-factor 2