Moving forward when working with text like this, I would highly recommend working with Inkscape on your computer and converting your text into an actual SVG, this will allow you to ensure that everything is engraved vs the results like you got originally. If you want to do different sections of lettering different shades, use Inkscape to change the color on each section you want to specifically change so that you’ll be able to have that as its own step.
Hope this helps!