Root level category, tag, author and archive pages to work

I want root level WordPress urls to work for category, tag, author and archive page.
For example right now categories pages are.

domain.com/category/cat-name/

it shows posts under cat-name category.
But if someone visits

domain.com/category/

it shows 404 error, page not found.
I want all these URLs to show some unique content created specifically for each link.

domain.com/category/
domain.com/tag/
domain.com/author/
domain.com/archive/

How can we do that?

It is not possible by default. Your only possible way out of this is to create custom page templates which you can modify to display something like an index or any custom content

When you create a new page in the back-end, choose this custom template, and make sure that your page slugs is named accordingly so that when you visit

domain.com/category/

that this custom page template is being displayed