Mark those are neat!
What are those lines? (Yellow circles) Is that from the engraving?
Are you able to do a spiral fill? You should be able to get a prismatic look.
Diamond drag?
What I usually do if I have any objects within text is separate them.
For instance, the rhombus trapazoid funky shape with the M.
I would engrave the shape slightly less into the surface than the M.
Once the M is engraved it is more pronounced and is a tad deeper.
Engraving the M & shape as a whole procduces unwanted results.
Maybe its the way it calculates the 'route'. Give it a try sometime.