Add 'access site.login true' to every page on page creation through Admin

is there a way to add the this frontmatter

access:
    site.login: true

by default to every page created via the admin? Specifically, without having to manually add it in ‘expert’ mode. I just want it to be there always when a user creates a new page via the admin so I don’t have to go through and manually add it after. I’m trying to keep all pages on root private.

I’ve tried something like

header.access.site.login:
  type: bool
  default: true

But no luck.

This is my current blueprints for a new page:

title: Default

form:
  fields:
    tabs:
      type: tabs
      active: 1

      fields:
        header:
          type: tab
          title: Header

          fields:
            header.taxonomy:
              type: taxonomy
              label: PLUGIN_ADMIN.TAXONOMY
              multiple: false
              validate:
                required: true
                type: array

            header.title:
              type: text
              label: Article Title
              validate:
                required: true

            header.header_intro:
              type: editor
              label: Header Intro

            header_boxes:
              type: columns
              fields:
                header_box1:
                  type: column
                  fields:

                    header.header_audience:
                      type: list
                      max: 6
                      style: vertical
                      label: Audience
                      fields:
                        .text:
                          type: text
                          label: List Item
                        .tooltip_text:
                          type: text
                          label: Tooltip Text

                header_box2:
                  type: column
                  fields:

                    header.header_readers_feelings:
                      type: list
                      max: 6
                      style: vertical
                      label: "Reader's Feelings"
                      fields:
                        .text:
                          type: text
                          label: List Item

                header_box3:
                  type: column
                  fields:

                    header.header_our_tone:
                      type: list
                      max: 6
                      style: vertical
                      label: Our Tone
                      fields:
                        .text:
                          type: text
                          label: List Item


        body:
          type: tab
          title: Body

          fields:
            header.body_content:
              type: editor
              label: Body Content
              # codemirror:
              #   # mode: 'markdown'
              #   indentUnit: 4
              #   autofocus: true
              #   indentWithTabs: false
              #   lineNumbers: true
              #   styleActiveLine: true
              #   # gutters: ['CodeMirror-lint-markers']
              #   # lint: true

            header.body_media:
              label: Upload or Choose Images
              type: pagemedia
              # destination: 'user/themes/my-theme/assets'
              # multiple: true
              # limit: 10
              # filesize: 8
              # accept:
              #   - image/*


        tips:
          type: tab
          title: Tips

          fields:
            header.tips_section_title:
              type: text
              label: Tips Section Title

            header.tips_item:
              type: list
              max: 30
              style: vertical
              label: Add a Tip
              fields:
                .tip_title:
                  type: text
                  label: Tip Title

                .tip_body:
                  type: textarea
                  label: Tip Copy

                .tip_no_copy:
                  type: textarea
                  label: Tip Example - NO

                .tip_yes_copy:
                  type: textarea
                  label: Tip Example - YES



        related:
          type: tab
          title: Related Articles

          fields:
            header.related_pages:
              type: list
              max: 5
              style: vertical
              label: Add Related Pages
              fields:
                .related_page_link:
                  # type: text
                  # label: Tip Title
                  type: pages
                  size: large
                  label: Select a Page
                  show_all: false
                  show_modular: false
                  show_root: false
                .related_page_link_text:
                  type: text
                  label: Override Link Text (optional)
                  validate:
                    required: false

You might want to look at How to create default FrontMatter for my Docs pages.