Laser low output

Hello everyone.
I’m trying to engreave/cut( 3 mmMDF as a test material) with my 5.5 w diode laser engraver with poor results.
I’ve been using LaserGRBL, but since I decided to try Lightburn few days ago I’ve been having the same issue.
I had to add the device manually selecting GRBL as Controller, gaining the control of the machine without problems.
Yet every shape or image that I try to engrave/cut result like the power output was way lower (like 1/4 comparing to the same test file with LaserGRBL).
I searched for an answer in the troubleshooting session and in the forum, finding the page GRBL: Low or No Power Output, but after changing the S-Value max in the device settings to match the $30 in my laser firmware, as suggested in the page, nothing changed.
Could somebody help me understand why?

And this is set to mm/min?