String substitution in Views Contextual filter parameter?

In Drupal 9, I have a View called News.

The View is displayed at the following path:

/news

I can edit it at the following path:

/admin/structure/views/view/news/edit

It has the following Contextual filter:

Content datasource: Content type

The contextual filter values are provided by the URL.

When the filter value is NOT in the URL: Provide default value

Type: Fixed

Fixed value: all

Exception value: all

If this value is received, the filter will be ignored; i.e, "all values"

This works well for content types like article and blog_post.

When the View is displayed for the path /news/article, the contextual filter shows only Content type article.

When the View is displayed for the path /news/blog_post, the contextual filter shows only Content type blog_post.

So far, so good.

Now, the client has a custom content type called "Youtube Video" with machine name youtube_video.

When this View is displayed for the path /news/youtube_video. the contextual filter shows only Content type youtube_video.

But the client wants the path to be /news/video.

What are my options?

Some constraints:

• The client definitely wants the path to be /news/video, and not something like /news?type=video.
• I don't think that it's trivial to match /news/foo and substitute bar for foo as the input for a contextual filter.
• I know how to use positional parameters in a route, but I don't think I can easily override the route for just /news/foo while preserving the contextual filter as it is for the other content types.

Some flexibility:

• The Drupal 9 site is brand new, and I'm about to migrate the content from Drupal 7 via Migrate API, so it's possible to change the machine name of the youtube_video content type to video during the migration. Then this View would work without modification. (The problem would be figuring out everything else that references the machine name youtube_video and changing that to video also -- potentially a lot of effort.)
• It may be possible to alter the query parameters conditionally using hook_views_pre_view() or hook_views_query_alter(), but I only want to do this if a specific parameter is matched.

Here's my first working proof-of-concept based on the answer above:

/**
 * Implements hook_view_pre_view().
 */
function my_module_views_pre_view(ViewExecutable $view, $display_id, array &$args) {
  if ($view->id() == 'news' && isset($args[0])) {
    if ($args[0] == 'video') {
      $args[0] = 'youtube_video';
    }
  }
}

The first arg in the path /news/video actually just calls the View with $view_id = 'news', so the contextual filter parameters don't start until the second segment in that path, which is $arg[0].

And it's important to check that $arg[0] is set before checking its value; otherwise, the /news path will throw errors when no filters are passed.

Finally, in my case there's no need to check for a specific $display_id, since I want the string substitution to occur for all displays of this particular View.

Other than that, the answer above got it just right.