@apex This is what I did and it worked fine. The result is UTC anyway, so I don't know if there is a format that can be used to replace that. But I am just removing that part from the String and then formatting it:
// imports at the top
use Carbon\Carbon;
use Illuminate\Support\Str;
Carbon::createFromFormat('D M d H:i:s Y', Str::replaceFirst('UTC ', '', 'Tue Sep 03 01:21:59 UTC 2019'))