The trick is to set the work origin properly. Yes luban should just be able to generate gcode that the machine understands, but that doesn’t seem to be the case. Instead, you must think of how your work is oriented vs the work origin in luban, and then make sure you move the toolhead to that point in the bed and use the “set work origin” on the touchscreen to set the origin.
I eventually figured it out, not sure if you’ve seen my post, but I tried to go into super n00b detail (since I’m still a n00b in laser): How to: Laser cutting with camera capture
Also, once you get a single good run from luban, it might be worth considering lightburn. I spent a day or so learning the quirks of lightburn, and it was much easier than dealing with the quirks of luban.