Remove the Flood Unblock module as it will be discontinued by its maintainers in favour of using the Flood Control module instead, which now contains the functionality

✅ Update Release Notes and Update Helper on new feature change/addition

    varbase_security_update_9001:
        '#title': 'Remove the Flood Unblock module as it will be discontinued by its maintainers'
        '#description': '
        <p>In favour of using the Flood Control module instead, which now contains the functionality.</p>
        <p>See issue <a href="https://www.drupal.org/i/3250823" target="_blank">#3250823</a> for details.</p><br />'
        '#description_successful': '<p class="messages messages--status">This update is successfully implemented.</p><br />'
        '#description_failed': '
        <p class="messages messages--warning">This update failed to be done automatically.<br />
        <span class="icon-help">Try running drush varbase-up --force varbase_core varbase_security_update_9001 to force applying this update.</span>
        This will likely override your previous configuration! Do this on your own risk.<p><br />
        '

Feedback by Razem

Make it 1 update checkbox only, not 2.

    varbase_security_update_9001:
        '#title': 'Add Flood Control module for login attempt limiting and remove the Flood Unblock module as it will be discontinued by its maintainers'
        '#description': '
        <p>This update adds security hardening policies and rules such as rate limiting for password requests and login attempt limiter.</p>
        <p>See issue <a href="https://www.drupal.org/i/3250823" target="_blank">#3250823</a> and <a href="https://www.drupal.org/i/3187308" target="_blank">#3187308</a> for details.</p><br />'
        '#description_successful': '<p class="messages messages--status">This update is successfully implemented.</p><br />'
        '#description_failed': '
        <p class="messages messages--warning">This update failed to be done automatically.<br />
        <span class="icon-help">Try running drush varbase-up --force varbase_security varbase_security_update_9001 to force applying this update.</span>
        This will likely override your previous configuration! Do this on your own risk.<p><br />
        '