I came up with this process while working with another UCCNC user. See if it works for you.
Based on the last test I think I have a procedure to make this work.
- Setup a device type as Marlin in LightBurn.
- In Device Settings make sure S Value Max is set to 255
- In Device Settings make sure to select M03/M05 for Laser Control Command
- Create your design, then push “Save GCode” in Laser window and select a filename
- Open the saved G-code in a text editor and make the following changes:
Replace all 'M05' with 'M11'
Replace all 'M03 S' with 'M10Q'
Add a line with just 'M3' before the first line with 'M11'
- Run g-code in your control software
More on the background of this in this thread: