[mega menu support for menu-4 & menu-5] #WordPress

functions.php

<?php
/**
 * Support menu-4, menu-5 on MegaMenu.
 * Default: Only Support primary, secondary, menu-3 menus
 */
add_filter( 'astra_nav_mega_menu_support', 'custom_megamenu_support', 10, 1 );
function custom_megamenu_support( $nav_menus ) {
	$nav_menus[] = 'menu_3';
	$nav_menus[] = 'menu_4';
	return $nav_menus;
}