I checked machine and device settings. I did not see an option for “best for diode” mm/min. I also did not find the machine speed you mentioned. I’ve provided some screenshots below to better illustrate what I am seeing.
This is for a Comgrow z1 10w laser. And the drivers are installed but lightburn never detected the unit so if there are additional settings to be made, I simply do not know what or where as I am still learning.