Personally I think it is an order of operation issue.
- turn on your laser.
- Plug USB into Mac
- open LightBurn
- In LightBurn “Laser” window, hit drop down to left of ‘devices’. It should have cu.BLTH, cu.Bluetooth-incoming-port, cu.SOMETHING
The cu.SOMETHING is probably your laser. Select it and see if you get a ‘ready’