I don’t even know what else to say, how is “color” not the right value for “icon_pressed_color” (i tried with and without putting it brackets already, same error)
icon_pressed_color is a theme override, the docs are oddly displaying it as if it’s a normal property but you have to set it through .set or .add_theme_color_override; I prefer .set because right-clicking the property in the inspector gives the “Copy Property Path” option