Displaying a pdf that is stored in a remote storage

I have a script that uploads a image file or pdf to a remote server using SFTP. The script should also display the uploaded file. The upload part is running as expected but the file doesn't display, instead, what appears to be another image is displayed (it seems to be a screenshot of one of my projects, I don't know where it is stored). What is wrong?

routes:

Route::get('/file-upload', [FileController::class, 'showUploadForm']);
Route::post('/file-upload', [FileController::class, 'store']);
Route::get('/file/{filename}', [FileController::class, 'serveFile']);

Controller:

<?php
namespace App\Http\Controllers;
use Illuminate\Http\Request;
use App\Models\File;
use Illuminate\Support\Facades\Storage;

class FileController extends Controller
{
    public function showUploadForm()
    {
        $files = File::all();
        return view('upload', compact('files'));
    }
    public function store(Request $request)
    {
        $request->validate([
            'file' => 'required|mimes:pdf|max:2048', // Example validation rules
        ]);

        $path = Storage::disk('sftp')->putFile('uploads', new \Illuminate\Http\File($request->file('file')));

        File::create(['name' => $path]);

        return redirect()->back()->with('message', 'File uploaded successfully.');
    }

    public function serveFile($filename)
    {
        $disk = Storage::disk('sftp');

        if (!$disk->exists($filename)) {
            abort(404, 'File not found');
        }

        $fileData = $disk->get($filename);

        // Determine the MIME type
        $tempFilePath = sys_get_temp_dir() . '/' . $filename;
        file_put_contents($tempFilePath, $fileData);
        $mimeType = File::mimeType($tempFilePath);
        unlink($tempFilePath);

        return response($fileData, 200)
            ->header('Content-Type', $mimeType);
    }
}

View:

<form action="/file-upload" method="post" enctype="multipart/form-data">
    @csrf
    <input type="file" name="file">
    <button type="submit">Upload</button>
</form>
@if (session('message'))
    <p>{{ session('message') }}</p>
@endif

@foreach($files as $file)
    {{ $file->name }}
    <br>
    <embed src="{{ $file->name }}" width="600" height="400">
@endforeach