I work with a lot of acrylic and if it’s something like the angel where you want to have a seamless look the defocus can help smooth it. Increased LPI (lines per inch) can help as well because you’re getting overlap to burn more material. LPI can be changed in the manual settings or by clicking the arrow to the right of the proofgrade settings. Have no fear of losing the PG settings, they reset.
Most importantly DO NOT walk away from acrylic while it is engraving especially if you change settings. It can easily catch on fire.