Filter WordPress posts by multiple taxonomy terms with AJAX and pagination

filter-posts-mt-terms.php

<?php
/**
 * Check if term exists
 */
if (!is_array($terms)) :
    $response = [
        'status'  => 501,
        'message' => 'Term doesn\'t exist',
        'content' => 0
    ];

    die(json_encode($response));
else :

    foreach ($terms as $tax => $slugs) :

        if (in_array('all-terms', $slugs)) {
            $all = true;
        }

        $tax_qry[] = [
            'taxonomy' => $tax,
            'field'    => 'slug',
            'terms'    => $slugs,
        ];
    endforeach;
endif;

/**
 * Setup query
 */
$args = [
    'paged'          => $page,
    'post_type'      => 'post',
    'post_status'    => 'publish',
    'posts_per_page' => $qty,
];

if ($tax_qry && !$all) :
    $args['tax_query'] = $tax_qry;
endif;

$qry = new WP_Query($args);