This - there are 3 options when engraving.
Vary Power is the “smoothest” but it will also engrave at different depths depending on how dark the area its engraving is.
Convert to Dots uses the same technology newspapers do to get shading - at a high enough value you cannot see the individual dots, only the shading they create
Convert to Patterns is similar to Dots, but I find gives a smoother look on large areas.
You should test all three on a small scrap to decide what look you like, and then try it on your mahogany.