If it’ any help…
This video
https://youtu.be/8fUg6ebWut0 is Mach4 but it demonstrates just how an unused Axis Direction Pin can be used to switch the laser ON/OFF and a PWM signal to control laser power for a combined engraving and cutting toolpath.
The attached pic was laser produced on some scrap plywood using the Pokeys 57CNC controller.
The Mach3 motion controller I use on a daily basis is the Warp9 ESS.
Tweakie.