Not possible to manually add an UploadedFile to $request->files

For various reasons, I need to duplicate an uploaded file so that it appears twice on the $request->files but with a new name

I've tried with a Middleware like the code below, tried with set, add, by instantiating UploadedFile, etc.. but none of the 'newname' ones will appear when calling $request->allFiles() later on in a Controller

public function handle($request, Closure $next)
{
        if($request->hasFile('file')){ //True uploaded file

            $request->files->add(['newname1' => \Illuminate\Http\UploadedFile::createFromBase($request->file('file'))]);

            $request->files->set('newname2', \Illuminate\Http\UploadedFile::createFromBase($request->file('file')));

            $request->files->set('newname3', $request->file('file'));

            $fileVar = new \Symfony\Component\HttpFoundation\File\UploadedFile($uploadedFile->getPathname(),
                $uploadedFile->getClientOriginalName(),
                $uploadedFile->getClientMimeType(),
                $uploadedFile->getClientSize(),
                $uploadedFile->getError());

            $request->files->set('newname4', $fileVar);
        }

        return $next($request);
}

However, $request->allFiles() will only show the 'file' which is the one posted from an HTML form but none of the others