There’s no way to get the result you’re looking for. The Folder view will only show music files, but not videos, in a Music library.
The Global Folder process outlined in that Help page will only cause the videos to appear on the Artist Detail page, like this:
The Inline Videos process will cause them to appear like this:
You can create a Library of the “Other Videos” type to have music videos in their own library (and Folder View will show them), but that will be its own library, separate from your Music library.
