Laravel multi-lang url translation not working – SEO

I work on a multi-lang webapp and therefore I also need to handle URLs translated to different languages (for SEO reasons). I’m following the guidelines from this article (second answer), but got stuck with a basic problem. Please see below my web.php:

<?php

use IlluminateSupportFacadesLang;
use IlluminateSupportFacadesRoute;

$all_langs = config('app.all_langs');

//Iterate over each language prefix 
foreach( $all_langs as $prefix ){
    Route::group(['prefix' => $prefix , 'middleware' => 'localization'], function() use ($prefix) {
        if ($prefix == '') $prefix = 'en';
        
        Route::get(Lang::get('routes.home',[], $prefix), 'HomeController@index')->name('home');


    });
}

I though that the above code snippet will generate a route that is based on the german translation of ‘home’: for example de/hause (for testing purposes only).

Instead of this the route generated has the URI routes.home, feeling like that the translation did not work. Additionally my translation files (lang/en/routes.php and lang/de/routes.php) are printed out at the top of the page (why is this happening?). Please see the generated route:list illustrating this below:

Ors-MacBook-Pro:gng_backo Ors$ php artisan route:list
return array(
'home' => 'home',
'tours' => 'tours',
'guides'   => 'guides'
'login' => 'login'
);return array(
'home' => 'hause',
'tours' => 'touren',
'guides'   => 'stadtfuehrer'
);+--------+----------+----------------+------+-------------------------------------------+------------+
| Domain | Method   | URI            | Name | Action                                    | Middleware |
+--------+----------+----------------+------+-------------------------------------------+------------+
|        | GET|HEAD | api/user       |      | Closure                                   | api        |
|        |          |                |      |                                           | auth:api   |
|        | GET|HEAD | de/routes.home | home | AppHttpControllersHomeController@index | web        |
|        |          |                |      |                                           | auth       |
|        | GET|HEAD | en/routes.home | home | AppHttpControllersHomeController@index | web        |
|        |          |                |      |                                           | auth       |
+--------+----------+----------------+------+-------------------------------------------+------------+

REFERENCES:

My localization middleware:

<?php

namespace AppHttpMiddleware;

use App;
use Closure;

    class Localization
    {
        /**
         * Handle an incoming request.
         *
         * @param  IlluminateHttpRequest  $request
         * @param  Closure  $next
         * @return mixed
         */
        public function handle($request, Closure $next)
        {
            
            //setting of the locale based on the first segment of the URL
            app()->setLocale($request->segment(1));
            return $next($request);
        }
    }

My kernel:

protected $middlewareGroups = [
    'web' => [
        AppHttpMiddlewareEncryptCookies::class,
        IlluminateCookieMiddlewareAddQueuedCookiesToResponse::class,
        IlluminateSessionMiddlewareStartSession::class,
        // IlluminateSessionMiddlewareAuthenticateSession::class,
        IlluminateViewMiddlewareShareErrorsFromSession::class,
        AppHttpMiddlewareVerifyCsrfToken::class,
        IlluminateRoutingMiddlewareSubstituteBindings::class,
        AppHttpMiddlewareLocalization::class,
    ],

    'api' => [
        'throttle:60,1',
        IlluminateRoutingMiddlewareSubstituteBindings::class,
    ],
];

/**
 * The application's route middleware.
 *
 * These middleware may be assigned to groups or used individually.
 *
 * @var array
 */
protected $routeMiddleware = [
    'auth' => AppHttpMiddlewareAuthenticate::class,
    'auth.basic' => IlluminateAuthMiddlewareAuthenticateWithBasicAuth::class,
    'bindings' => IlluminateRoutingMiddlewareSubstituteBindings::class,
    'cache.headers' => IlluminateHttpMiddlewareSetCacheHeaders::class,
    'can' => IlluminateAuthMiddlewareAuthorize::class,
    'guest' => AppHttpMiddlewareRedirectIfAuthenticated::class,
    'password.confirm' => IlluminateAuthMiddlewareRequirePassword::class,
    'signed' => IlluminateRoutingMiddlewareValidateSignature::class,
    'throttle' => IlluminateRoutingMiddlewareThrottleRequests::class,
    'verified' => IlluminateAuthMiddlewareEnsureEmailIsVerified::class,
    'localization' => AppHttpMiddlewareLocalization::class,
];

Lang folder: