Unable to remove index.php on IIS 10

I think I need to solve my URI_PROTOCOL problem first. Without setting $config['index_page'] = "index.php?", I can't get any page to load except the default page. Like the documentation says, I've rotated through all the possible options for URI Protocol, but none of them work. I was using "Auto" in my old environments.

Code:

/*
|--------------------------------------------------------------------------
| URI PROTOCOL
|--------------------------------------------------------------------------
|
| This item determines which server global should be used to retrieve the
| URI string.  The default setting of 'REQUEST_URI' works for most servers.
| If your links do not seem to work, try one of the other delicious flavors:
|
| 'REQUEST_URI'    Uses $_SERVER['REQUEST_URI']
| 'QUERY_STRING'   Uses $_SERVER['QUERY_STRING']
| 'PATH_INFO'      Uses $_SERVER['PATH_INFO']
|
| WARNING: If you set this to 'PATH_INFO', URIs will always be URL-decoded!
*/
$config['uri_protocol']    = 'REQUEST_URI';

Because none of these options worked, I added a "?" to my index.php as recommended by the troubleshooting page: https://www.codeigniter.com/user_guide/i...oting.html