The device setup in LightBurn just tells it how big the working area of the machine is supposed to be. The machine itself has the settings that convert distances into the moves made by the motor, and if those are wrong, the output will be wrong.
The steps per mm values can be changed in Edit > Device Settings at the bottom. Unroll the X & Y axis settings and change the steps per mm setting. Doubling them will make the motors travel twice the distance, for example.
For the location issues, read through this (at the bottom for homing, but the rest is useful to review as well):