[WooCommerce core] Use this snippet to adjust the button text for sold-out products in the product catalog view.

wc-replace-catalog-button-text-sold-out-products

/**
* Change add to cart button text to "Sold Out" for out-of-stock products
 * (except variable products, which keep their normal text like "Select options").
 */
function custom_sold_out_button_text( $text, $product ) {
    if ( ! $product instanceof WC_Product ) {
        return $text;
    }
    $type = $product->get_type();
    // Keep default text for variable products and variations
    if ( $type === 'variable' || $type === 'variation' ) {
        return $text;
    }
    // For all other product types, if it's out of stock, label it as "Sold Out"
    if ( ! $product->is_in_stock() ) {
        return __( 'Sold Out', 'woocommerce' );
    }
    // Otherwise, keep the default text
    return $text;
}

add_filter( 'woocommerce_product_add_to_cart_text', 'custom_sold_out_button_text', 10, 2 );