error running a gui application on systemd services - shell

Question

I am trying to run a gui commands in systemd services which i want it to execute on system startup.
these are my files.
oversteer.sh file:
#!/bin/bash
sleep 1s
export DISPLAY=:99.0
export SCREEN_WIDTH=1200
export SCREEN_HEIGHT=960
export SCREEN_DEPTH=24
export GEOMETRY="${SCREEN_WIDTH}x${SCREEN_HEIGHT}x${SCREEN_DEPTH}"
sudo oversteer --autocenter 45 &
sudo oversteer --range 720
oversteer.service file:
[Unit]
Description = oversteer
After=local-fs.target
[Service]
Environment="DISPLAY=:0"
Environment="XAUTHORITY=/home/ubuntu/.Xauthority"
ExecStart=/home/ubuntu/g29_steering_wheel/autostart_scripts/oversteer.sh
Restart=on-failure
Type=simple
StandardOutput=journal+console
[Install]
WantedBy=multi-user.target
I have put this file in /etc/systemd/system and have given executable as well as root permissions. However, it looks like this service fails because of no Display.
error is as follows:
Unable to init server: Could not connect: Connection refused
Unable to init server: Could not connect: Connection refused
Unable to init server: Could not connect: Connection refused
Unable to init server: Could not connect: Connection refused
(oversteer:8052): Gdk-CRITICAL **: 08:00:50.744: gdk_cursor_new_for_display: assertion 'GDK_IS_DISPLAY (display)' failed
(oversteer:8053): Gdk-CRITICAL **: 08:00:50.763: gdk_cursor_new_for_display: assertion 'GDK_IS_DISPLAY (display)' failed
Traceback (most recent call last):
File "/usr/lib/python3/dist-packages/matplotlib/backends/backend_gtk3.py", line 45, in <module>
cursors.MOVE : Gdk.Cursor.new(Gdk.CursorType.FLEUR),
TypeError: constructor returned NULL
I am running on raspi 4 with ubuntu 20.04. The oversteer is a package for controlling the parameters of my joystick.