Laravel 5.4集合sortByDesc无法正常工作

I have two queries with Eloquent which I collect and merge and after i do sortByDesc but it's not sorting collection.

$f_games = collect(Game::with('fUser', 'sUser')->where('first_user_id', Auth::user()->id)>get());
$s_games = collect(Game::with('fUser', 'sUser')->where('second_user_id', Auth::user()->id)->get());

$response = $f_games->merge($s_games)->sortByDesc('id');

There is no need to wrap in collect(), $f_games and $s_games will be collection without additional wrapping:

$f_games = Game::with('fUser', 'sUser')->where('first_user_id', Auth::user()->id)>get();
$s_games = Game::with('fUser', 'sUser')->where('second_user_id', Auth::user()->id)->get();
$response = $f_games->merge($s_games)->sortByDesc('id');

But the best way is:

$user_id = Auth::user()->id;

$f_s_games = Game::with('fUser', 'sUser')
             ->where('first_user_id', $user_id)
             ->orWhere('second_user_id',$user_id)
             ->orderBy('id', 'desc')
             ->get();