Look up Blueprint structure asset as it generates custom ustruct. You might as well just bind blueprint structure asset, with that your users would able to reuse the type in blueprints outside of your plugin
Ironocly, it’s stupidly easy on C++ side as user would just make struct and do metadata entry USTRUCT() or use some common base struct, then find UStruct object with it. You might consider that as a extra feature to make your plugin C++ usable.
Or just make UStruct selectable, so both blueprint and C++ structs can be picked