PHP function that retrieves an array with all the taxonomies of certain WordPress Post Type.

get_taxonomies_tree.php

<?php
//===============================================
// PHP function that retrieves an array with all 
// the taxonomies of certain WordPress Post Type.
// By: SamuraiPetrus
//===============================================

// $taxonomies = get_object_taxonomies('your-post-type');
// Codex get_object_taxonomies : https://developer.wordpress.org/reference/functions/get_object_taxonomies/

function get_taxonomies_tree ($taxonomies) {
	$tax_tree = [];

	foreach ( $taxonomies as $tax ) {
		if ( isset($tax) ){
			$args = ["taxonomy" => $tax];
			$tax_content = [];
			$tax_terms = get_terms($args);
			if (!empty($tax_terms)) {
				foreach ($tax_terms as $t) {
					$tax = get_taxonomy($t->taxonomy);
				}
				if ($tax) {
					$tax_title = $tax->label;
				}else{
					$tax_title = "Categorias";
				}
				array_push($tax_content, $tax_title);
				array_push($tax_content, $tax_terms);
				array_push($tax_tree, $tax_content);
			}
		}
	}

	return $tax_tree;
}