nested JS Scripts are not included on wordpress page (using wp_enqueue_scripts in functions.php)

Question

I have a problem with wordpress and wp_enqueue_scripts.

I want to include selected scripts only on specific posts. For example: domain.com/post123/ <- script post123.js should be included. And to display the content within the post, I am using shortcodes.

PROBLEM: The scripts of the second wp_enqueue_scripts are not included (regarding the following setup)

functions.php

...
//in the functions.php I require 
require("assets/shortcodes/custom-shortcodes.php");
...

custom-shortcodes.php

function load_custom_shortcode_scripts(){
    if(is_single(208)) require("files-208/script-208.php");
    // others might follow
}

add_action( 'wp_enqueue_scripts', 'load_custom_shortcode_scripts');

script-208.php

 function script_enqueue_stroop() {   
       wp_register_script( "gamescript_stroop", get_stylesheet_directory_uri() . '/assets/shortcodes/stroop/stroop.js', array('js-jquery') );

       wp_localize_script( 'gamescript_stroop', 'ajaxLoad', array( 'ajaxUrl' => admin_url( 'admin-ajax.php' )));

       wp_enqueue_script( 'gamescript_stroop' );
}
add_action( 'wp_enqueue_scripts', 'script_enqueue_stroop' );

Everything is working fine until it reaches the wp_enqueue_scripts in the last file (208.php).

The stroop.js is not included in the code and it looks like wordpress is not processing the last wp_enqueue_scripts hook. If I write an "echo 'test'; in the script_enqueue_stroop() function, there is no response.

I thought it might be a problem with having a nested wp_enqueue_scripts within a wp_enqueue_scripts?

Version 2 And I tried to change the setup just slightly to prevent the nested wp_enqueue script like this:

custom-shortcodes.php (adaption)

function load_custom_shortcode_scripts(){
    if(is_single(208)){

        wp_register_script( "gamescript_stroop", get_stylesheet_directory_uri() . '/assets/shortcodes/stroop/stroop.js', array('js-jquery') );
        wp_enqueue_script( 'gamescript_stroop' );
        wp_localize_script( 'gamescript_stroop', 'ajaxLoad', array( 'ajaxUrl' => admin_url( 'admin-ajax.php' )));
        
       require("files-208/script-208.php");
    }
    // others might follow
}

add_action( 'wp_enqueue_scripts', 'load_custom_shortcode_scripts');

Like this the file is included properly but I get this error:

XHR POST domain.com/wp-admin/admin-ajax.php 400 Bad Request

by the way: Everything was working without any problems before I added the is_single(POSTID) ..., but the script was loaded on every single page (what is absolutely unnecessary)

Any ideas? I am struggling with this for a few days now and can't find a working solution. Thanks a lot :-)