@adam-nagy - thank you for your response!
The error you get (the 'undefined' TypeError) is the same error I get if I try loading through the console directly in B360's viewer. But there I can also see the DiffTool source code being present when inspecting 'Sources' through the browser's dev tools. That is not the case in our own app - here the DiffTool source code is fx not present at all. I have also tried the snippet that you use in your test project (so loading with a config), but it doesn't seem to work for me (see image) - I still get the same error.
Screenshot of loading with config
Seeing as the DiffTool seem to not be present at all, I wonder if there's something wrong in our base setup?