do you want to get 50 items ? then do this
$todos = $this->user->todos()->take(50)->get(['id', 'title', 'body', 'completed', 'created_by']);
OR
$todos = $this->user->todos()->paginate(50);
return response()->json($todos->toArray());
If you are creating an API user Laravel API https://laravel.com/docs/8.x/eloquent-resources#resource-collections technique