Show Custom Post Type in Upfront Layouts list. Upfront hides 'product' CPT as it relies to ecommerce plugin, this filter will show the CPT in Upfront Layouts list if the CPT was manually created and does not rely on an ecommerce plugin

show-cpt-upfront-layout.php

<?php
/*
Plugin Name: CPT in Upfront Layouts
Plugin URI: https://premium.wpmudev.org/
Description: Display CPT in Upfront existing layouts list
Version: 1.0
Author: Lindeni Mahlalela @ WPMUDEV
Author URI: https://premium.wpmudev.org/
License: GPLv2 or later
*/

//TAGS: Upfront, CPT, CustomPress, Upfront Layouts
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

add_filter('upfront-builder_skip_exported_layouts', 'ufb_unhide_product_cpt', 999, 2 );
function ufb_unhide_product_cpt($default, $layout){
	$item = explode('-', $layout['item'] );
	$post_type = $item[1];
	
	$post_types = array('product'); //add other post types here
	if ( post_type_exists ( $post_type ) && in_array( $post_type, $post_types ) ) {
		return false;
	}
}

If you want to reveal all hidden post types you only need to add them in the '$post_types' list like so:

$post_types = array('product', 'movies', 'etc');