The Lighting Controller

When assigning a color to a button, the result is not the color i selected. For example when selecting "strong Blue" the result is light blue on the button.

Edit: also when creating a colored image (for example in microsoft paint) with a fixed color and using it as button image in the live view, the result in the live view is not the color i created.

This is normal.
There is an additional "bright" layer over the color, in order to always be able to read the text in the button.

That can be done with drop shadow behind the text or something. Or only placing a layer behind the text, not on the whole button.
When having multiple premixed colors (for example Dark blue, Light Blue, Purple, Purple-Red) it's almost impossible to visually see the difference on the screen in the current situation. All color differences are dissapearing because of the extra layer.

I see your problem. What about a white or lighter colored rectangle behind the text? Or a color transition from light color in the center (where the text is) to original color at the outer side of the button?

Visible text is not the only issue.