Ubuntu - GPU - Mesa - Install Mesa Utilities - Install the Ernst Sjöstrand - Mesa Unstable driver

ALERT: Trying to get rid of this PPA is very difficult due to broken dependencies.

To install Ernst Sjöstrand - Mesa Unstable Mesa driver than what comes with Ubuntu.

WARNING: This uses a PPA.

WARNING: Installing new Mesa graphics drivers may also require a newer Linux kernel.

It will be a good idea to enable HWE kernel on Ubuntu to reduce the chances of conflict with the kernel.
HWE Kernel gives you the latest stable kernel used by Ubuntu on an older LTS release.

Install the Ernst Sjöstrand Unstable Mesa PPA driver

The Ernst Sjöstrand Unstable Mesa Driver PPA provides a much newer, but unstable release of Mesa.

sudo add-apt-repository ppa:ernstp/mesaaco
sudo apt update
sudo apt upgrade

NOTE: This will provide the bleeding edge Mesa with LTO (Link-Time Optimizations).

If you are facing issues and do not want to use the newer version of Mesa, you can revert to the original version.

Install PPA Purge tool first:

sudo apt install ppa-purge

And then use it to remove the PPA as well as the Mesa package version installed by this PPA.

sudo ppa-purge ppa:ernstp/mesaaco