Screen tearing when using xrandr and x11vnc on Ubuntu 20.04

I am trying to use my android phone as a second monitor for my Ubuntu. I am following this blog.

This is the 20-virtual.conf in /usr/share/X11/xorg.conf.d

Section "Device"
 Identifier "intelgpu0"
Driver "intel"
Option "VirtualHeads" "1"
EndSection

and this is the script for the virtual desktop and VNC server

#!/bin/bash

W=798      # Virtual display width
H=393      # Virtual display height
O=VIRTUAL1  # The name of the virtual display (check using xrandr)
P=eDP1      # The name of your physical display (check using xrandr)
PW=$(xrandr --current | grep \* | awk '{print $1;}' | cut -d x -f 1)

# Create the virtual display
gtf $W $H 60 | sed '3q;d' | sed 's/Modeline//g' | xargs xrandr --newmode
gtf $W $H 60 | sed '3q;d' | sed 's/Modeline//g' | awk '{print $1;}' | sed 's/^.\(.*\).$/\1/' | xargs xrandr --addmode $O
gtf $W $H 60 | sed '3q;d' | sed 's/Modeline//g' | awk '{print $1;}' | sed 's/^.\(.*\).$/\1/' | xargs xrandr --output $O --right-of $P --mode
    
# Forward the VNC port to your device and start a VNC session
adb reverse tcp:5900 tcp:5900
x11vnc -localhost -clip ${W}x${H}+${PW}+0

# When the session ends, turn off the virtual display
xrandr --output $O --off

Image of the desktop after running the script

Also sometimes the system freezes and only the mouse works (then I have to either reboot the system or restart the gdm)

In the file /usr/share/X11/xorg.conf.d/20-virtual.conf change the driver to "modesetting"

This is how your 20-virtual.conf file should look

Section "Device"
    Identifier "intelgpu0"
    Driver "modesetting"
    Option "VirtualHeads" "1"
    Option "TearFree" "true"
EndSection