Amazing work on getting a working Marlin/MPCNC post processor file. I envy your knowledge of coding. I have only just started learning C+ with the Arduino IDE, it’s slow going without any prior experience, but very rewarding and fun. I got into it to build toys/robots for my son.
I am really impressed with Fusion 360, and have used it quite a bit over the last couple of months to design and print upgrades for my 3d printer. Prior to finding Fusion 360 I was using FreeCAD, but found it quite obtuse, with a very steep learning curve. I achieved more in my first hr using Fusion 3d, than I did in a week with FreeCAD (that was after spending hours watching tutorials lol). IMO it is by far the most easy and user friendly CAD I have found.
I very much look forward to exploring the CAM capabilities of Fusion 360 once my MPCNC is complete. In the mean time I will be following this thread closely.