How can I completely hide a taxonomy term from “frontend”? [closed]

First what i see in your “latest FAIL” code you use wrong “operator” (or maybe is just typo). It sholuld work if you change “operator” to 'operator' => 'NOT IN'
tax query parameters

UPDATE:
for Sablednah comment

You can try to hide this term (and “count”) completely by modify WP_Term_Query with something like that:

add_action('pre_get_terms', 'my_pre_get_terms');
function my_pre_get_terms( $query ) {
    if (is_admin())
        return;

    //if you know term_id you can just set it - "$termIdForExclude = 1234567" and skip next piece of code until "if ( isset( $query->query_vars['include'] ) && !empty( $query->query_vars['include'] ) ) {"
    remove_action('pre_get_terms', 'my_pre_get_terms');//avoid infinite loop
    $termForExclude = get_term_by('slug', 'stock_record', 'product_type');
    add_action('pre_get_terms', 'my_pre_get_terms');//avoid infinite loop
    if ( $termForExclude instanceof WP_Term ) {
        $termIdForExclude = $termForExclude->term_id;
    } else {
        return;
    }

    //modify query_vars
    if ( isset( $query->query_vars['include'] ) && !empty( $query->query_vars['include'] ) ) { //if query has include exclude is ignored
        $include = wp_parse_id_list( $query->query_vars['include'] );
        $hasId = array_search( $termIdForExclude, $include );
        if( $hasId ) {
            unset( $include[$hasId] );
        }
        $query->query_vars['include'] = ( is_array($query->query_vars['include']) ) ? $include : implode(', ', $include);
        if( !empty($include) ) {
            return;
        } 
    }

    if ( isset( $query->query_vars['exclude'] ) ) {            
        $exclude = wp_parse_id_list($query->query_vars['exclude']);
        if (!in_array($termIdForExclude, $exclude)) {  
            $exclude[] = $termIdForExclude;
        }
        $query->query_vars['exclude'] = ( is_array($query->query_vars['exclude']) ) ? $exclude : implode(', ', $exclude);
    } else {            
        $query->query_vars['exclude'] = $termIdForExclude;
    }                
}