A bit delayed in looking at this again, and no other offerings 
Where are all the Gimp artists.
First the Gimp version: Since neither the Gimp flatpak or Appimage are working with your installation as far as gmic is concerned. Have you considered the Gimp 2.10.8 from the 'buntu PPA https://launchpad.net/~otto-kesselgulasc...buntu/gimp Directions for use is top of the page.
Gimp is a RGB editor so those CMY sliders in PS are not there. However just using Gimp tools you might get something like this.
Sort of 'synth-like' Uses Colors -> Components -> Decompose to CMY images
The cyan and magenta images are adjusted with Colors -> Color Curves The yellow is filled with black to remove it.
Then Colors -> Components -> Recompose to adjust the original image.
There is a 4 attachment limit per reply, so no more screenshots just another video
direct link: https://youtu.be/z8GsLKgES-k duration 3 minutes
Where are all the Gimp artists.First the Gimp version: Since neither the Gimp flatpak or Appimage are working with your installation as far as gmic is concerned. Have you considered the Gimp 2.10.8 from the 'buntu PPA https://launchpad.net/~otto-kesselgulasc...buntu/gimp Directions for use is top of the page.
Gimp is a RGB editor so those CMY sliders in PS are not there. However just using Gimp tools you might get something like this.
Sort of 'synth-like' Uses Colors -> Components -> Decompose to CMY images
The cyan and magenta images are adjusted with Colors -> Color Curves The yellow is filled with black to remove it.
Then Colors -> Components -> Recompose to adjust the original image.
There is a 4 attachment limit per reply, so no more screenshots just another video
direct link: https://youtu.be/z8GsLKgES-k duration 3 minutes