To remove a highlight on text currently, the initial highlight color must be selected and clicked twice. There's no "simple" option to remove a highlight from text. The recommended feature is an X option to delete it more quickly (single step). In some apps, the X is independent of the colors and on the same line. In others, the X is over the color of the current highlight (see attached screen shot). On IOS, there is a bar that indicates "None." Perhaps this is just a feature missing on Mac OS. Any of these options would work better over the current method on Mac OS.
Thank you,
Dan