There's quite a lot of libraries using Qt and one of the pitfall is that even if there's Qt in the name it does not make them an official Qt module nor a supported Qt library. However, it is still valid to ask questions about them here as there might be a chance that one, or more, forum members might have experience with it.

@agoose77 Then a composite widget is the way to go as you have done. Just as a note from other post in case you want inspiration. https://github.com/paceholder/nodeeditor