Show slug based CPT single page from external directory

slug-based-cpt-single-page.php

<?php 

function custom_section_single_template($single) {
	global $post;

	if ($post->post_type == 'section' && is_single()) {
			$slug = $post->post_name;

			if ($slug === 'catalog') {
					return get_template_directory() . '/section-templates-single/single-section-catalog.php';
			} elseif ($slug === 'banner') {
					return get_template_directory() . '/section-templates-single/single-section-banner.php';
			} elseif ($slug === 'banner-five') {
					return get_template_directory() . '/section-templates-single/single-section-banner-five.php';
			}
	}

	return $single;
}
add_filter('single_template', 'custom_section_single_template');