Order posts base on last favorite post by user

To order favorite posts based on the last post favorited by a user, you need to modify the query to include the post IDs in the order they were favorited by the user

WP does not directly store the order of favorites, you might need to store this information separately, for example, in user meta

Try general approach

Store Favorite Order When a user favorites a post, store the post ID and timestamp in the user meta.

Retrieve Favorite Order Retrieve the favorite order for the current user from user meta.

Order Posts Use the retrieved favorite order to order the query results

// Function to get favorite order from user meta
function get_favorite_order($user_id) {
    $favorite_order = get_user_meta($user_id, 'favorite_order', true);
    // Convert stored data to array if not empty, otherwise return empty array
    return $favorite_order ? explode(',', $favorite_order) : array();
}

// Function to update favorite order in user meta
function update_favorite_order($user_id, $favorite_order) {
    update_user_meta($user_id, 'favorite_order', implode(',', $favorite_order));
}

// Get current user ID
$current_user_id = get_current_user_id();

// Get favorite order for current user
$favorite_order = get_favorite_order($current_user_id);

// Get favorite posts
$favorites_query = new WP_Query(array(
    'post_type' => 'download',
    'posts_per_page' => 6,
    'ignore_sticky_posts' => true,
    'meta_key' => 'simplefavorites_count',
    'orderby' => 'post__in', // Order by the post IDs in the favorite order
    'post__in' => $favorites_order,
));

// Output favorite posts
if ($favorites_query->have_posts()) {
    while ($favorites_query->have_posts()) {
        $favorites_query->the_post();
        // Output post content
    }
    wp_reset_postdata();
} else {
    // No favorite posts found
}