Well I´am a mechanical engineer and have over 45 yrs experience in the steel construction. So i have constructed many objects im my life but using the basic elements like steel and Aluminium. In the last 10 yrs designing for the aerospace Industry using industrial Lasers
Lasers dont cut all materials equally. The most obvious example is the amount of power required to cut aluminum vs mild steel. Its nearly double for aluminuum. As you get close to your machine limits you cut quality starts to degrade rapidly.
So...you work in a material your machine can handle. If you dont take that into consideration you shouldnt own the machine.
I build Giant scale RC planes. the best wood i have worked with is 3mm birch plywood . it cuts nice and has a lot of strength. of course i use balsa wood as well but the thinner the material you work with the finer cut results you will get. so try to laminate layers to build thick panels never try to cut material thicker than 6mm and expect to have neat cuts.