ctrlpanel/app/Classes/Settings/Language.php

<?php

namespace App\Classes\Settings;

use App\Models\Settings;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Cache;
use Illuminate\Support\Facades\Session;
use Illuminate\Support\Facades\Validator;

class Language
{
    public function __construct()
    {

    }

    public function updateSettings(Request $request)
    {
        $validator = Validator::make($request->all(), [
            'autotranslate' => 'string',
            'canClientChangeLanguage' => 'string',
            'defaultLanguage' => 'required|string',
            'languages' => 'required|array',
            'languages.*' => 'required|string',
            'datatable-language' => 'required|string',
        ]);

        if ($validator->fails()) {
            return redirect(route('admin.settings.index').'#language')->with('error', __('Language settings have not been updated!'))->withErrors($validator);
        }

        $values = [
            //SETTINGS::VALUE => REQUEST-VALUE (coming from the html-form)
            'SETTINGS::LOCALE:DEFAULT' => 'defaultLanguage',
            'SETTINGS::LOCALE:DYNAMIC' => 'autotranslate',
            'SETTINGS::LOCALE:CLIENTS_CAN_CHANGE' => 'canClientChangeLanguage',
            'SETTINGS::LOCALE:AVAILABLE' => 'languages',
            'SETTINGS::LOCALE:DATATABLES' => 'datatable-language',
        ];

        foreach ($values as $key => $value) {
            $param = $request->get($value);

            if (is_array($param)) {
                $param = implode(',', $param);
            }

            Settings::where('key', $key)->updateOrCreate(['key' => $key], ['value' => $param]);
            Cache::forget('setting'.':'.$key);
            Session::remove('locale');
        }

        return redirect(route('admin.settings.index').'#language')->with('success', __('Language settings updated!'));
    }
}