I worked with a stepcraft user a while back to come up with a method to generate gcode that worked for him. We arrived at using a Marlin profile but it’s possible your LinuxCNC method is better/easier. I hadn’t explored it. Take a look at this post:
I believe you can achieve this by changing the Origin in Device Settings. If you only want to invert the Y, then flip the vertical position of the origin. For example, if it’s currently top-left, switch to bottom-left. If bottom-right, switch to top-right.