Can you not do the axis swap and then use G18 (XZ), G19 (YZ) for arcs? You can swap the axes around in Fusion and basically assign any axis as a rotary axis. Many times I post different operations separately and merge the G code to do things that I would not normally be able to do, especially using live tooling in the lathe. Fusion can generate 5 axis tool paths.

This is kind of what we did here to make a couple of these parts, the CNC lathe was busy and we didn't want to do these on the manual lathe. I can't recall if we used turning or 3D milling for this operation.