setLocale not working

I am configuring a multilanguage app. The user is visiting the app as a guest (I wonder if this is related).

My default language in config/app.php is pt-BR. I created a database table called languages, where I save the languages available for the app.

Languages model

Schema::create('languages', function (Blueprint $table) {
    $table->id();
    $table->string('iso2');
    $table->string('name');
    $table->string('native');
    $table->timestamps();
});

I have a dropdown in the navigation bar where the user can select the language. Then, when the page loads, I get the locale from the session to display as the desired locale/language.

<x-dropdown align="right" width="48">
    <x-slot name="trigger">
        <button >
            <div class="flex">
                <x-flag :name="app()->getLocale()" />
            </div>

            <div class="ml-1">
                svg for down array
            </div>
        </button>
    </x-slot>

    <x-slot name="content">
        @foreach ($languages as $lang)
            <x-dropdown-link :href="route('language', $lang->iso2)" >
                <x-flag :name="$lang->iso2" />
                <span class="ml-2">{{ $lang->native }}</span>
            </x-dropdown-link>
        @endforeach
    </x-slot>
</x-dropdown>

Web route for setting the language:

Route::get('lang/{language:iso2}', [LocalizationController::class, 'index'])->name('language');

When the user select the language, a request is sent to this controller.

LocalizationController.php

public function index(Language $language)
{
    session()->put('locale', $language->iso2);
    return redirect()->back();
} 		

And I defined this middleware: App\Http\Middleware\Localization

<?php

namespace App\Http\Middleware;

use Closure;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\App;

class Localization
{
    /**
     * Handle an incoming request.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  \Closure(\Illuminate\Http\Request): (\Illuminate\Http\Response|\Illuminate\Http\RedirectResponse)  $next
     * @return \Illuminate\Http\Response|\Illuminate\Http\RedirectResponse
     */
    public function handle(Request $request, Closure $next)
    {
        if (session()->has('locale')) {
            Carbon::setLocale(session()->get('locale'));
            App::setLocale(session()->get('locale'));
        }
        return $next($request);
    }
}

I also registered the middleware in kernel.php

protected $middleware = [
        \App\Http\Middleware\Localization::class,
        ...
    ];

But when I select a locale other than pt-BR, nothing happens. The locale from the session changes, but when I dd on middleware like

dump("Locale session value in localization middleware: ",session()->get('locale') );

The locale is null, but if I print session()->get('locale') in the view, the locale is the one that I selected in the dropdown, but the app locale is still pt-br. I don't understand why this is happening. Does anyone have a clue?