Saves a WordPress user's last login and puts it in a sortable column in the WordPress dashboard

user-last-login-wordpress.php

<?php
//Record user's last login to custom meta
add_action( 'wp_login', 'smartwp_capture_login_time', 10, 2 );

function smartwp_capture_login_time( $user_login, $user ) {
  update_user_meta( $user->ID, 'last_login', time() );
}

//Register new custom column with last login time
add_filter( 'manage_users_columns', 'smartwp_user_last_login_column' );
add_filter( 'manage_users_custom_column', 'smartwp_last_login_column', 10, 3 );

function smartwp_user_last_login_column( $columns ) {
	$columns['last_login'] = 'Last Login';
	return $columns;
}

function smartwp_last_login_column( $output, $column_id, $user_id ){
	if( $column_id == 'last_login' ) {
    $last_login = get_user_meta( $user_id, 'last_login', true );
    $date_format = 'M j, Y';
    $hover_date_format = 'F j, Y, g:i a';
    
		$output = $last_login ? '<div title="Last login: '.date( $hover_date_format, $last_login ).'">'.human_time_diff( $last_login ).'</div>' : 'No record';
	}
  
	return $output;
}

//Allow the last login columns to be sortable
add_filter( 'manage_users_sortable_columns', 'smartwp_sortable_last_login_column' );
add_action( 'pre_get_users', 'smartwp_sort_last_login_column' );

function smartwp_sortable_last_login_column( $columns ) {
	return wp_parse_args( array(
	 	'last_login' => 'last_login'
	), $columns );
 
}

function smartwp_sort_last_login_column( $query ) {
	if( !is_admin() ) {
		return $query;
	}
 
	$screen = get_current_screen();
 
	if( isset( $screen->base ) && $screen->base !== 'users' ) {
		return $query;
	}
 
	if( isset( $_GET[ 'orderby' ] ) && $_GET[ 'orderby' ] == 'last_login' ) {
 
		$query->query_vars['meta_key'] = 'last_login';
		$query->query_vars['orderby'] = 'meta_value';
 
	}
 
  return $query;
}

//Add [lastlogin] shortcode
function smartwp_lastlogin_shortcode( $atts ) {
  $atts = shortcode_atts(
  array(
      'user_id' => false,
  ), $atts, 'lastlogin' );

  $last_login = get_the_author_meta('last_login', $atts['user_id']);
  if( empty($last_login) ){ return false; };
  $the_login_date = human_time_diff($last_login);
  return $the_login_date; 
}

add_shortcode( 'lastlogin', 'smartwp_lastlogin_shortcode' );

$query in smartwp_sort_last_login_column( $query ) is passed by reference. There's no need to return $query.

Also, note that $screen->id is users-network for network admins.

@IanDelMar thank you, going to modify the code with these comments