Diode lasers and cutting are just not a good combination. And I’m speaking as someone with a 5.5W diode laser bolted to my CNC. I just used a Loc-Line hose zip-tied to my laser for air assist, connected to my compressor. Works well for keeping the path clear.
Use the laser to engrave. Use the CNC to cut. Use the right tool for the job.
I have had no issue with my 7w output blue LED laser when cutting 3mm balsa or similar wood. Not sure what the difference with 3mm MDF other than probably various wood type and the glue. I cut this with 2 passes at 80%. (It is on a 3018 PRO also)