Custom meta_query order for Elementor based on post meta key [closed]

Assuming that you want to get posts with that meta key, regardless of content, and order by that meta value, you would need to set two properties.

1. meta_query
2. orderby

So the code, based of your question would be like this

// Custom query to order 'recommended reading' posts by populatrity
add_action('elementor/query/my_custom_filter', function ($query) {
    if (empty($meta_query = $query->get('meta_query'))) $meta_query = [];

    // add our condition to the meta_query
    $meta_query['google_unique_page_views'] = [
        'key'     => 'google_unique_page_views',
        'compare' => 'EXISTS',
    ];

    // set the new meta_query
    $query->set('meta_query', $meta_query);

    // set the new orderby
    $query->set('orderby', [
        'google_unique_page_views' => 'DESC' // or ASC, based on your needs
    ]);
});