Can I pass a variable within a conditional statement on archive?

I want to say if is subcategory of category X, display posts like this

I can’t find how to do this anywhere, so I’m trying to write my own variable to use…
Here’s the function:

/**
* https://alex.leonard.ie/2011/04/20/wordpress-get-id-of-top-level-parent-category/
* Returns ID of top-level parent category, or current category if you are viewing a top-level
*
* @param    string      $catid      Category ID to be checked
* @return   string      $catParent  ID of top-level parent category
*/
function pa_category_top_parent_id ($catid) {
 while ($catid) {
  $cat = get_category($catid); // get the object for the catid
  $catid = $cat->category_parent; // assign parent ID (if exists) to $catid
  // the while loop will continue whilst there is a $catid
  // when there is no longer a parent $catid will be NULL so we can assign our $catParent
  $catParent = $cat->cat_ID;
 }
return $catParent;
}

Here’s how I’m using it to return the ID of the current category IF it’s parent category is 33

<?php
 	$catid = get_query_var('cat');
		$parent = pa_category_top_parent_id ($catid);
	if( $parent == '33'	) {
		$subcatid = get_query_var('cat');
	}?>

I can get it to echo on the page (<strong><?php echo $subcatid ; ?></strong>), but it won’t work inside my conditional statement to return true/display what I want on archive.php:
if (is_category('16') || in_category('16') || is_category('33') || is_category( $subcatid ) ) { }

Can you even do this? Please help!!!