variables empty when sent to API endpoint in Laravel

I’m trying to send a set of form inputs from a controller into an API endpoint but when I check the variables in the API, it all shows null value.. what is wrong with my code?

CulinaryController.php

    public function update(Request $request, Culinary $culinary)
    {
        $client = new Client();
        $token = Session('token');

        try {
            $multipart = [];

            foreach ($request->except('cover_photo') as $key => $value) {
                $multipart[] = [
                    'name' => $key,
                    'contents' => $value,
                ];
            }
            
            if ($request->hasFile('cover_photo')) {
                $coverPhoto = $request->file('cover_photo');
                $multipart[] = [
                    'name' => 'cover_photo',
                    'contents' => fopen($coverPhoto->getRealPath(), 'r'),
                    'filename' => $coverPhoto->getClientOriginalName(),
                ];
            }
            dd($multipart);
            
            $url = 'http://localhost/api/v1/culinary/'.$culinary->id;
            $response = $client->put($url, [
                'multipart' => $multipart,
                'headers' => [
                    'Authorization' => 'Bearer '.$token,
                    'Accept' => 'application/json',
                ]
            ]);
        } catch (Exception $e) {
            return redirect()->back()->withErrors(['errors' => $e->getMessage()])->withInput();
        }
    }

api/v1/CulinaryController.php

    public function update(Request $request, Culinary $culinary)
    {
        return response()->json([
            'status' => 'test',
            'request' => $request->all(),
            'foo' => request('title'),
            'file' => $request->file('cover_photo'),
            'culinary' => $culinary,
        ]);
    }

routes/api.php

    Route::apiResource('culinary', CulinaryController::class);

when I uncomment the dd($multipart) in the controller, it contains 7 sets of input below so I’m sure the form wasn’t empty when submitted.

array:9 [▼ // appHttpControllersAdminCulinaryController.php:198
  0 => array:2 [▼
    "name" => "_token"
    "contents" => "TwpS0e7OJH1jhhR1dr8RBpCiYKW4vhVyuk3CRZWC"
  ]
  1 => array:2 [▼
    "name" => "_method"
    "contents" => "PUT"
  ]
  2 => array:2 [▼
    "name" => "title"
    "contents" => "Et in quia ut et illo harum."
  ]
  3 => array:2 [▼
    "name" => "old_cover_photo"
    "contents" => "https://via.placeholder.com/640x480.png/0022bb?text=distinctio"
  ]
  4 => array:2 [▼
    "name" => "country_id"
    "contents" => "188"
  ]
  5 => array:2 [▼
    "name" => "category_name"
    "contents" => "vegetarian"
  ]
  6 => array:2 [▼
    "name" => "prologue"
    "contents" => "Adipisci iure nihil sit voluptatem rerum voluptatibus. Qui aperiam et magnam corrupti quia eius reprehenderit. Sunt non aut dolores. Dolorem nesciunt atque ipsa
 ▶
"
  ]
  7 => array:2 [▼
    "name" => "body"
    "contents" => "Autem iure qui magni excepturi hic. Laudantium adipisci saepe odio quod cupiditate. Blanditiis occaecati sint at sint incidunt optio illum nihil."
  ]
  8 => array:2 [▼
    "name" => "opening_hours"
    "contents" => "Qui et magnam labore a ea corrupti."
  ]
]