How to increase touchpad speed beyond 'Accel Speed' maximum on Ubuntu 18.04

My touchpad speed is too slow (it takes me two full swipes to get the mouse from one side of the screen to the other). This might be because I'm on a 4K monitor. I have increased the touchpad speed to its maximum setting in the Ubuntu 18.04 Settings. I have also checked the speed setting in the terminal using xinput, e.g.

xinput --list --short

Which returns 15 as the device ID of my touchpad. When I execute xinput --list-props 15, the libinput Accel Speed is 1. According to the libinput docs, this must be in the range [-1,1] and is thus at the maximum value. Is there a way to increase the mouse speed further?

List all properties in your mouse/touchpad using xinput --list-props 11 (MY TOUCHPAD ID IS 11, yours will be different) and see the id of the property Device Accel Constant Deceleration. Now type the command xinput --set-prop 11 268 0.3 (MY TOUCHPAD DECELERATION PROPERTY ID IS 268, yours will be different) to decrease your mouse/touchpad deceleration. Since it's pretty tedious to type these two commands everytime you Log in, put these two commands in the end of the /home/{your user name}/.bashrc file so that these get executed automatically whenever you Log in.

This solution has a minor error though. With time, you'll notice that your mouse/touchpad ID will often switch between a couple of values. You may also have seen that. Instead of using the device ID you can use its name as shown in --list-props. You may then use xinput --set-prop "SYNA8005:00 06CB:CD8C Touchpad" 268 0.3 instead of using the ID.