Found this on pcgamingwiki
Increase sharpening beyond the in-game limit through the config file
[14]
- Go to the configuration file(s) location.
- Open system.xml in a text editor.
- Find the sharpenIntensity line (e.g. <sharpenIntensity value="1.000000" />).
- Increase the value as desired (e.g. <sharpenIntensity value="3.800000" />).
- Save the file.
Accessing in-game Graphics settings will revert the changes.
Setting the file to read-only will preserve the chosen value for the next game launch.
It does make a difference.