Last I checked Duet can’t raster engrave all that fast at all. The gCode it takes is based on Marlin, which is very verbose and not as efficient. Also, LightBurn doesn’t support Duet at this time.
Cohesion3D does do the things faster, as well as being purpose built for laser cutter control, and works very well with LightBurn.
If you do want to use the C3D to run a diode, there are some nuances to be aware of and I can point you to resources in the C3D forum.