Dan Griffiths

Do you develop websites for a living? Do you prefer to give your clients a level of access other than Administrator to prevent accidental damage? Maybe even a custom role? What if you wanted to hide the Admin user(s) from them altogether? This plugin does exactly that!
Currently based off the ‘update_core’ permission, Remove Administrators hides all references to Admins from all other user roles on the dashboard. The next release will support configurable permissions and multisite installations.
<h3>Todo</h3>
<ul>
<li>Add support for configurable permissions</li>
<li>Add support for WordPress Multisite installations</li>
</ul>

Remove Administrators

Allows admins to hide the admin role from all other roles.

Alvaro Gómez

This plugin restricts access for Authors and Contributors so they can only see their own Media Library uploads.
This has two main uses: Make it easier for Authors to locate their own uploads when Media Libraries grow very big and prevent Authors from using or downloading media that belongs to other users.
Admins and Editors will still be able to see everyone’s uploads.

Restrict Media Library Access

Muy útil

This plugin works fine in WP 5.7.1 

It's just the example code from the official WP docs for the ajax_query_attachments_args filter, with a line added to check if the current user is an administrator. It's very simple.

There's no reason this plugin shouldn't work in an up-to-date WP installation

works in WP 5.7.1

Restricts access for Authors and Contributors so they can only see their own Media Library uploads.

Remove Administrators vs Restrict Media Library Access