I don’t recognize that laser module, or the board you’re connected to for it. I think my best suggestion would be to check with the seller to make sure it’s wired correctly, and see if they have any tests you can do to make sure it’s working correctly.
The code to fire the laser with the Fire button and the code that drives the laser when running is basically the same. The only thing that might be different between those two is speed - if you ask the laser to go faster than it’s allowed to by the limits set in the firmware, it will reduce the laser power output to compensate.
You could try running really slow to see if it gives you a better burn. If it does, check the $110 and $111 settings to see what the maximum speed your board is set to allow. GRBL defaults for those are really low. (500mm/min, I think)