I have the X20 Pro. Yeah the extra bits add up fast.
The deepest cut I have made so far is 6mm MDF. 90% power 100mm/min one pass. So rather slow. But (and this is important) to get that result I had to focus the laser at 1mm from the surface rather than the normal 4mm. This puts the smallest focus of the laser somewhere in the middle of the work piece. Without this it could not quite make the cut all the way through in one pass (two would have done it easy).
My laser was not without issues out of the box. See: https://forum.lightburnsoftware.com/t/atomstack-x20-pro-teething-issues-poor-qc/71672
Support were fairly responsive. They would answer by email within a day. They did end up refunding me the cost of replacement wheels.