The file you have provided has many issues, with duplicate objects, crossing paths to name a few. If you zoom in to the upper-left of your art you can see what I am describing. This file would require significant edits to produce a good laser ready file regardless of how it is output (Fill or Line).
How was this SVG created? Do you also have this art in a high-res lossless image format like PNG? I ask as you could import that and try the ‘Tools’->‘Trace Image’ to reproduce the vectors without all the issues I am seeing in your original file.
