In my opinion AX or X would be preferable; people don't usually say "AmigaOne" anyway.
AmigaOne is pretty stupid. But in keeping they should call the new machines "PointOne"
So it would be called AmigaOne PointOne. The different variations can be handled with a slash.
AmigaOne PointOne/P5020
When a new motherboard is created it will become a PointTwo.