The part looks good. What metal is that? What is the profile of the engraving bit? I have been experimenting with different bits from 90deg to 30deg and a few different brands. For the 30deg bits it is easy to break the tip if I go to fast. My machine has a top RPM of 3000 which is very slow for engraving.
One more suggestion. I you have speeds that you think are reasonable then use that for a while to gain comfort and experience. Then over time slowing do things to optimize the speed one step at a time. I run my machine must faster than when I started a couple of years ago but I could also go faster. Another thing to consider is how many of something your going to make. If I am only going to make 1 or 2 then the run time on the machine is a small percent of the time it takes to make the part when you consider the CAD/CAM, Fixture and sometimes G-Code debugging. So I don't speed too much time trying to optimize the speed of a part. If I was going to make 100 parts, well that would justify some investment in speed optimization.