WordPress Yoast plugin.
how to get only one category and if selected (Primary Category) Primary than get the (Primary Category) Primary selected

function display_terms_name( $taxonomy ) {
    $post_id = get_the_ID(); // Get the current post ID
    $primary_category = '';
    $default_category_links = '';

    // Get all the terms for the post (categories in this case)
    $terms = get_the_terms( $post_id, $taxonomy );

    // If terms exist and no errors
    if ( $terms && ! is_wp_error( $terms ) ) :
        
        // If the Yoast SEO plugin is active and the WPSEO_Primary_Term class exists
        if ( class_exists( 'WPSEO_Primary_Term' ) && $taxonomy === 'category' ) {
            // Get the primary category ID
            $primary_term = new WPSEO_Primary_Term( 'category', $post_id );
            $primary_category_id = $primary_term->get_primary_term();
            
            // If a primary category is set
            if ( $primary_category_id ) {
                $primary_category = get_category( $primary_category_id );
                
                // Display the primary category and limit to one
                echo '<ul>';
                echo '<li><a href="' . esc_attr( get_term_link( $primary_category->slug, $taxonomy ) ) . '">' . __( $primary_category->name ) . '</a></li>';
                echo '</ul>';
                
                return; // If primary category exists, stop further execution
            }
        }

        // If no primary category is set, loop through all categories (or terms)
        // but only display the first one
        foreach ( $terms as $term ) {
            echo '<ul>';
            echo '<li><a href="' . esc_attr( get_term_link( $term->slug, $taxonomy ) ) . '">' . __( $term->name ) . '</a></li>';
            echo '</ul>';
        }

    endif;
}