User Post Type – display user links for upt_user post items

<?php

// Add to your (child) theme's functions.php

add_filter( 'post_link', function( $url, $post ) {
    if ( 'upt_user' == get_post_type( $post->ID ) ) {
        $user_id = UPT()->get_user_id( $post->ID );
        $url = get_author_posts_url( $user_id );
    }
    return $url;
}, 10, 2 );