Laravel dependencies does not update in XAMPP

The case:

I want to install Laravel on my computer (info: Linux 5.11.0-27-generic #29~20.04.1-Ubuntu SMP Wed Aug 11 15:58:17 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux)

When I ran composer create-project laravel/laravel exapp everything works fine, but dependencies are not installed to serve a Laravel project (./artisan serve).

I ran composer install but the vendor directory doesn't exist then I ran composer update && composer install but vendor director is not created.

Then I attempted to install dependencies by composer dump-autoload it gives me following error:

Generating optimized autoload files

Class Illuminate\Foundation\ComposerScripts is not autoloadable, can not call post-autoload-dump script

@php artisan package:discover --ansi

PHP Fatal error:  Uncaught Error: Class 'Illuminate\Foundation\Application' not found in /opt/lampp/htdocs/exapp/bootstrap/app.php:14

Stack trace:

#0 /opt/lampp/htdocs/exapp/artisan(20): require_once()
#1 {main}

  thrown in /opt/lampp/htdocs/exapp/bootstrap/app.php on line 14
Script @php artisan package:discover --ansi handling the post-autoload-dump event returned with error code 255

The vendor folder is created so I run php artisan serve and ./artisan serve the following error occurred;

PHP Fatal error:  Uncaught Error: Class 'Illuminate\Foundation\Application' not found in /opt/lampp/htdocs/exapp/bootstrap/app.php:14

Stack trace:

#0 /opt/lampp/htdocs/exapp/artisan(20): require_once()
#1 {main}
  thrown in /opt/lampp/htdocs/exapp/bootstrap/app.php on line 14

My path for xampp is /opt/lampp and I ran above commands in /opt/lampp/htdocs/exapp as superuser/root and as ordinary user.