I have created a plugin that lets Cura access HID mouse devices such as the 3Dconnexion Spacemouse. It's called RawMouse because the plugin interfaces directly to the raw device without the aid/hinderance of an operating system driver. It's not a sophisticated all-singing, all-dancing interface, it simply converts the HID mouse commands into the equivalent 2D mouse  commands.   It has been (vaguely) tested on Linux and Windows 10 and it should also function on MacOS (10.13 upwards).