Nuxt: does not generate separate routes if multiple slugs

Question

I have a content structure for education static website where the content is:

course
  subject
    chapter
      sections

My pages directory looks like this

pages
  _course
    _subject
      _chapter
        _section.vue
        index.vue // list of chapters of a subject of a coures
      index.vue  // list of subjects of a coure
    index.vue  // list of courses
  index.vue // home page 

My content structure is:

content
  c1
   s1
    ch1
      se111
      se112
    ch2
      se121
      se122
   ...

I have written the fetches and all works. Except that it does not create separate routes in the dist directory. It creates only one index.html.

My config

target: 'static',

  ssr: true,

  router: {
    base: '/'
  },

  generate: {
    fallback: '404.html'
  },
  ...

I find that only if I use one slug does it create separate route HTML in the dist directory

For example if I create pages as:

pages
  courses
     index.vue
  subjects
    _course
      index.vue // subjects of a course
  chapters
    _subject
      index.vue // chapters of a subject

It creates routes

I tried reading the generate documentation but could not figure out how exactly Nuxt uses the existing content to create different routes

Thanks for any help