Try Reshade in Zero-K!
It makes the game look more colorful, sharper - just better.
Download latest Reshade: https://reshade.me/
Move ReShade_Setup_4.2.1.exe in Spring folder. e.g.: C:\Program Files (x86)\Steam\SteamApps\common\Zero-K\engine\win32\104.0.1-1156-gb72a9cc
Click on "Select game to install..." and choose spring.exe. e.g.: C:\Program Files (x86)\Steam\SteamApps\common\Zero-K\engine\win32\104.0.1-1156-gb72a9cc\spring.exe
Click on "OpenGL".
Click "Yes" to download a collection of shaders.
Click on "OK".
Hit Home or Pos1 key for configuration and continue until finished.
I recommend to choose/tick, "Colorfulness, Clarity, Adaptive sharpen, Luma sharpen and vibrance"
But you can try all different shaders.
(view these 4 images fullscreen for sharpness)
(I disabled shadows, minimal graphic settings in Zero-K)
Before and after screenshots: https://imgur.com/a/u9U8jqm
(look at this unsharp, color-lacking soup and compare it to the sharp and colorful screenshot)
Reshade is working with most games.
You won't play any future games without reshade. :-)