Only show the admin user list when deleting a user and assing his content

functions.php

function delete_user_account( $query_args ) {
   
		// Use this array to specify multiple roles to show in dropdown
		$query_args['role__in'] = array( 'administrator' );
	   
		// Unset the 'who' as this defaults to the 'author' role
		unset( $query_args['who'] );
		
		return $query_args;
	}

	add_filter( 'wp_dropdown_users_args', 'delete_user_account' );	

Notes:
Add a condition so that it only run on the wp-admin/users.php?action=delete&user=#$%#$%#$%$#%#%#%# page