Same slug for Custom Taxonomy archive and CPT archive – Rewrite rule not working

I’m using a CPT (wg_seo_chat) together with a Custom taxonomy (wg_chat_category). Additional rewrite rules are in place to inject the Taxonomy into the URL:

CPT archive: domain/hilfe-chat
Taxonomy archive: domain/hilfe-chat/allgemein
Item page: domain/hilfe-chat/general/item

I’d like to keep the same slug /hilfe-chat/ for both CPT and Taxonomy archives, which seems to generate a conflict (404 for Taxonomy archives).

CPT

$rewrite = array(
        'slug'                  => 'hilfe-chat',
        'has_archive'           => 'hilfe-chat',

Custom taxonomy

$args = array(
            'rewrite'           => array('slug' => 'hilfe-chat')
        );

Rewrite rules for custom taxonomy

/** Rewrite rule to handle third level slug */

        function chat_cpt_generating_rule($wp_rewrite) {
            $rules = array();
            $terms = get_terms( array(
                'taxonomy' => 'wg_chat_category',
                'hide_empty' => false,
            ) );
           
            $post_type = 'wg_seo_chat';
        
            foreach ($terms as $term) {    
                        
                $rules['hilfe-chat/' . $term->slug . '/([^/]*)$'] = 'index.php?post_type=' . $post_type. '&wg_seo_chat=$matches[1]&name=$matches[1]';
                                
            }
        
            // merge with global rules
            $wp_rewrite->rules = $rules + $wp_rewrite->rules;
        }
        add_filter('generate_rewrite_rules', 'chat_cpt_generating_rule');

        /** Inject the chat category into the CPT Link */

        function change_link( $permalink, $post ) {
    
            if( $post->post_type == 'wg_seo_chat' ) {
                $chat_terms = get_the_terms( $post, 'wg_chat_category' );
                $term_slug = '';
                if( ! empty( $chat_terms ) ) {
                    foreach ( $chat_terms as $term ) {
        
                        // The featured chat will have another category which is the main one
                        if( $term->slug == 'featured' ) {
                            continue;
                        }
        
                        $term_slug = $term->slug;
                        break;
                    }
                }
                $permalink = get_home_url() ."/hilfe-chat/" . $term_slug . '/' . $post->post_name;
            }
            return $permalink;
        
        }
        add_filter('post_type_link',"change_link",10,2);

Any thoughts on how to resolve this conflict are much appreciated.

Thanks, Jan

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