First thanks for being so helpful on these forums, it seems like you are basically carrying them.
Question for you, if there is no way then how is it possible you can just copy and paste it into a Figma file? Wouldn’t that be not possible either?
Plugin API just doesn’t have this capability. The user can do it because they can copy-paste between files. Plugins can’t work between files in the first place, let alone copy something from one file to another. The fact that Figma supports a node from FigJam doesn’t mean you can create that node in Figma.