How to add template suggestion for user--VIEW-MODE--ROLE.html.twig
All you need to do is to get the current user object, get its roles, and then add the suggestion like in the following snippet. The current user also already is available in the $variables.

/**
 * Implements hook_theme_suggestions_HOOK_alter().
 */
function MYTHEME_theme_suggestions_user_alter(array &amp;$suggestions, array $variables) {

  // Define the view mode.
  $mode = $variables['elements']['#view_mode'];

  // Create a theme hook suggestion which has the view mode name in it.
  $suggestions[] = 'user__' . $mode;

  // Get current user.
  $current_user = $variables['elements']['#user'];

  // Get current user's roles.
  $roles = $current_user-&gt;getRoles();

  // Add suggestion per role.
  foreach ($roles as $role) {
    $suggestions[] = 'user__' . $mode . '__' . $role;
  }
}


This will give you:

&lt;!-- FILE NAME SUGGESTIONS:
   * user--full--administrator.html.twig
   * user--full--authenticated.html.twig
   * user--full.html.twig
   x user.html.twig
--&gt;