Without knowing what setting you’re using it’s hard to determine what needs adjustment - but in general increase your LPI to lessen those - it will increase the time though!
I have taken to using the method @geek2nurse came up with of doing 2 runs, one with vary power and one with SD engrave.
You also might want to increase the contrast on that image - if it looks a little blown out on the computer it’ll look better on the wood.