8 – How to uninstall pdf_reader module without error? “The ‘core’ or the ‘core_version_requirement’ key must be present”

In summary:
I cannot uninstall pdf_reader sucessfully without bringing down my site with this error:

DrupalCoreExtensionInfoParserException: The 'core' or the 'core_version_requirement' key must be present in modules/contrib/pdf_reader/pdf_reader.info.yml in DrupalCoreExtensionInfoParserDynamic->parse() (line 73 of core/lib/Drupal/Core/Extension/InfoParserDynamic.php).

( I did search the above error but cannot see anything related).

Have a Drupal 8.9.8 dev site using Composer 1.10.7
(I did try and update to composer 2 but that caused a lot of other errors, which I wanted to save for another day!)

I had pdf_reader installed and wanted to uninstall it.

Used composer to uninstall it:

drush pmu pdf_reader

This completes to success.

I then rebuild the cache with:

drush cache-rebuild

However I noticed in composer.json, there is still an entry:

"drupal/pdf_reader": "1.x-dev",

if I login to drupal and check the installed modules pages I can see it and it’s unticked.

At this point if I try and reinstall it using the UI I get the message:
PDF Reader is already installed.

If I look in the following directory, I can see the pdf_reader folder still exists
/web/modules/contrib/

If I now delete the above folder and clear the cache, it stops the website running with:

The website encountered an unexpected error. Please try again later.

DrupalCoreExtensionInfoParserException: The 'core' or the 'core_version_requirement' key must be present in modules/contrib/pdf_reader/pdf_reader.info.yml in DrupalCoreExtensionInfoParserDynamic->parse() (line 73 of core/lib/Drupal/Core/Extension/InfoParserDynamic.php).

At this point if I run:

drush cache-rebuild

I get a similar error:

In ExtensionDiscovery.php line 446:
                                                                               
  SplFileInfo::openFile(/var/www/html/web/modules/contrib/pdf_reader/pdf_read  
  er.info.yml): failed to open stream: No such file or directory        

(if I restore the pdf_reader folder and clear the cache the sites come back online).

So it seems like something is out of synch and/or not updating, any help appreciated (I’m far from a drupal expert, so I’m sure it’s something simple for an expert))

My Composer.json file:

{
    "name": "drupal/recommended-project",
    "description": "Project template for Drupal 8 projects with a relocated document root",
    "type": "project",
    "license": "GPL-2.0-or-later",
    "homepage": "https://www.drupal.org/project/drupal",
    "support": {
        "docs": "https://www.drupal.org/docs/user_guide/en/index.html",
        "chat": "https://www.drupal.org/node/314178"
    },
    "repositories": (
        {
            "type": "composer",
            "url": "https://packages.drupal.org/8"
        }
    ),
    "require": {
        "composer/installers": "^1.2",
        "drupal/admin_toolbar": "^2.3",
        "drupal/astrology": "^1.4",
        "drupal/bootstrap_barrio": "^5.1",
        "drupal/coffee": "^1.0",
        "drupal/copyright_footer": "^1.7",
        "drupal/core-composer-scaffold": "^8.8",
        "drupal/core-project-message": "^8.8",
        "drupal/core-recommended": "^8.8",
        "drupal/devel": "^4.0",
        "drupal/entity_delete": "^1.6",
        "drupal/fb_likebox": "^2.1",
        "drupal/feeds": "^3.0@alpha",
        "drupal/feeds_tamper": "^2.0@beta",
        "drupal/flexslider_fields": "^2.0",
        "drupal/fontawesome": "^2.17",
        "drupal/gdoc_field": "^1.1",
        "drupal/migrate_plus": "^5.1",
        "drupal/migrate_tools": "^5.0",
        "drupal/migrate_upgrade": "^3.2",
        "drupal/paragraphs": "^1.12",
        "drupal/pathauto": "^1.8",
        "drupal/pdf": "^1.0",
        "drupal/pdf_reader": "1.x-dev",
        "drupal/superfish": "^1.4",
        "drupal/tablefield": "^2.1",
        "drush/drush": "^10.3"
    },
    "conflict": {
        "drupal/drupal": "*"
    },
    "minimum-stability": "dev",
    "prefer-stable": true,
    "config": {
        "sort-packages": true
    },
    "extra": {
        "drupal-scaffold": {
            "locations": {
                "web-root": "web/"
            }
        },
        "installer-paths": {
            "web/core": (
                "type:drupal-core"
            ),
            "web/libraries/{$name}": (
                "type:drupal-library"
            ),
            "web/modules/contrib/{$name}": (
                "type:drupal-module"
            ),
            "web/profiles/contrib/{$name}": (
                "type:drupal-profile"
            ),
            "web/themes/contrib/{$name}": (
                "type:drupal-theme"
            ),
            "drush/Commands/contrib/{$name}": (
                "type:drupal-drush"
            ),
            "web/modules/custom/{$name}": (
                "type:drupal-custom-module"
            ),
            "web/themes/custom/{$name}": (
                "type:drupal-custom-theme"
            )
        },
        "drupal-core-project-message": {
            "include-keys": (
                "homepage",
                "support"
            ),
            "post-create-project-cmd-message": (
                "<bg=blue;fg=white>                                                         </>",
                "<bg=blue;fg=white>  Congratulations, you’ve installed the Drupal codebase  </>",
                "<bg=blue;fg=white>  from the drupal/recommended-project template!          </>",
                "<bg=blue;fg=white>                                                         </>",
                "",
                "<bg=yellow;fg=black>Next steps</>:",
                "  * Install the site: https://www.drupal.org/docs/8/install",
                "  * Read the user guide: https://www.drupal.org/docs/user_guide/en/index.html",
                "  * Get support: https://www.drupal.org/support",
                "  * Get involved with the Drupal community:",
                "      https://www.drupal.org/getting-involved",
                "  * Remove the plugin that prints this message:",
                "      composer remove drupal/core-project-message"
            )
        }
    }
}