Clean up controller(and bracket)?

Hi, I'm using a third party API with token auth. I'm "converting" the code to Laravel.

The Controller shows met the json output.

2 Questions:

1. All works well but I feel the code is not "using" the full use of Laravel maybe the login to get a token should be in a helper? Does anyone have a suggestion to clean it up or is it fine?

2. The json output creates a file with starting [ and ending bracket ] How can I remove that?

code:

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use Illuminate\Support\Facades\Http;
use Illuminate\Support\Facades\Cache;

class PostdataController extends Controller
{
    public function __construct()
    { 
 
    }

    public function index()
    {

        $postdata = Cache::remember('postcache', 60, function () 
        {
        
            $token = '';
            // LOGIN  
            $tokenURL = 'https://domain.com/api/token';
            $fields = array(
                'client_id'=>'Admin',
                'grant_type'=>'password',
                'username'=>'[email protected]',
                'password'=>'***',
                
            );
            
            $post = http_build_query($fields,'','&');
            $ch = curl_init ($tokenURL);
            curl_setopt($ch, CURLOPT_POST, 1);
            curl_setopt($ch, CURLOPT_POSTFIELDS, $post );
            curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
            $str = curl_exec($ch);
            curl_close ($ch);
      
            // GET TOKEN
            $token = json_decode($str);
            //print_r($token);
           
            $this->bearer = $token->token_type . ' ' . $token->access_token; 

            $response = Http::withHeaders(['Accept: application/json','Authorization: '.$this->bearer,])
                
                ->get('https://domain.com/api/reports/article/?id=bla');

                return json_decode($response);
       
       });
       return  $postdata;
    }
}

Thanks.