Seo – How to program the serving of two pages, accessible under the same URL, with only one of them getting indexed

Let’s say you have a website hosted on example.org. That website has a single page, whose content is static if the client requesting is not logged in, but dynamic (according to the logged client) if the client requesting it is logged in.

To properly handle this in terms of indexing on search engines, we currently thought of creating two separate files, let’s say logged_out.html and logged_in.php. When the URL (e.g. example.org) is requested, the PHP code checks if the current user is logged in, and if so, it requires logged_in.php, otherwise logged_out.html.
The logged_in.php has this in its head:

<meta name="robots" content="noindex,nofollow,noarchive">

As it does not make sense to index websites with dynamic contents in this system.

My question thus basically is how to program the serving / the routing of two pages, accessible under the same URL, with only one of them getting indexed. Such that the SE see only one and completely ignore the other one. Our current solution could be summed up like this:

// HTTP Request incoming to https://example.org/sample, which is routed to 
// present file via server configs 

if ($logged_in) {
  require ("logged_in.php") // should never be indexed / crawled
} else {
  require ("logged_out.html") // should be the indexed / crawled page
}

exit();

This should result in exclusively the contents of logged_out.html being indexed, and that for the URL https://example.org/sample, while the contents of logged_in.php should neither be indexed under any URL of example.org, nor be crawled.

Does our approach yield that intended result?