I have already read this thread and it just doesn’t work, kcolorchooser no longer shows a picker. I also tested all other apps without success picking up colors from the screen … https://forum.manjaro.org/t/color-picker-wayland/110853/13
Even when I open the app with env, the picker button is missing
That tool just has some bugs. The functions work including on wayland.
You can notice, for example, in the colorschemes settings you can open the edit dialog with an identical interface for choosing colors and the button is there.
This thread bashes it out a little - there are a few options, but the plasmoid is great, then I use simple text files open with Kate with colour previews… because kcolourchooser actually works.