If your design is in different coordinate space than your machine is setup for then something should be adjusted… Either fix the design so it fits the machine coordinate space or modify the machine coordinate space. Sure, some software guesses at what you’re intention is but others give you what you gave it.
That is not practical.
this is pecific to PCB world.
You take a sheet and you draw. on A4 in general.
I exactly applied your strategy: making the board in the right place from the start.
it doesn’t work either , the mirroring always flips relatively to Zero, so the coords will always be negatives .
the other Software’s do not guess, they go to a corner of the board and say this my Zero,Zero and whether is it left or right: I’ll make that direction valid.
LaserWeb should for instance: go PCB mode.
To implement this it is very easy:
Offset the plan X by the ((width of the board) / 2 ).
I’ll be more that happy to help, in case the devs. are interested in implementing PCB mode.
this is likely something like setting your workspace offset or something like that( G54 or something like that ). I’m not fluent with gcode but generally you put your workpiece on the table, load your file and set your workspace offset(probe?) so that both your material and your design align.
I suggest to create the gcode with LaserWeb and not load gcode created by other software.
If you load an SVG into LW, you can freely move the object around and scale or flip it. Then create the operation & gcode and run the job.
By the way: You can move the “work origin” by just clicking the “set zerro” button.
So for example, if your gcode object has a width of 100mm (in -x), then move the origin 100mm to the right and click “set zero”. This should move your objects left side to zero.