Zum Ändern des „Home“ Link bei den Breadcrumbs auf den Produkt- und Kategorie-Seiten kann folgender Code verwendet werden.
Breadcrumb Hook: Product- und Kategorie-Seiten

/**
* Filter the URL of the first breadcrumb item ("home"):
*
* @param string $home_url The default home URL to filter: get_home_url().
* @param string $url_start The URL start: If default language, empty. Otherwise "/{language_code}", like "/en".
* @param array $category_array The category array, the following breadcrumbs.
*/
function obs_breadcrumb_change( string $home_url, string $url_start, array $category_array ) {
return get_home_url( null, $url_start . '/shop/' );
}
// change the first breadcrumb item URL on product pages.
add_action( 'obs_product_breadcrumb_block_home_url', 'obs_breadcrumb_change', 10, 3 );
// change the first breadcrumb item URL on category pages.
add_action( 'obs_category_breadcrumb_block_home_url', 'obs_breadcrumb_change', 10, 3 );