Get Custom URL For Custom Taxonomy

‘ve got a custom post type called productpopups, and to sort them I have a custom taxonomy called productcategory. The post type has it’s own special template (single-productpopup.php) and I’m trying to show each products category with a link to the category. The problem I have is the following:

The link for each productcategory is say example.com/productcategory/category but the page I want to link it to is actually example.com/category

So I made up this:

<p>Categories:
<?php
$categories = get_the_terms( $post->ID, 'productcategory' );
foreach( $categories as $category ) {
    echo '<a href="https://example.com/'.$category->slug.'">'.$category->name.'</a>, ';
}
?>
</p>

This works because the pages I have set up use the same slugs as the productcategory, but its hacky and one slip (like a typo) will break it.

What I’d essential like to do is add a custom field to the taxonomy where I can specify the page url, and then be able to call that instead of the https://example.com/.$category->slug

Is this possible?