With PARA, the four types of folders are parallel structures.

Generally I prefer to nest Areas of Concern > Roles > Topic/Series/Client > Project > subfolders

I don't separate resources and projects, they are equivalent or combined.

Anything that needs to be archived to clean up the system is archived into a subfile. (ie. if I change a book cover, the previous cover files get archived within the book folder.)

Same general structure between my documents/notes/resources system and my project management/task system. A lot of what PARA considers projects, I would not consider a project and have a separate folder for. I have separate folders for things like writing and publishing a book, which is 150-200 tasks, not just 3-4. All of those little "projects" would show up under my Role.