Update Product Metadata Save Product Recursive problem

Hello i am updating the product meta data on the hook woocommerce_update_product.

The reason is i want to calculate some custom fields.

But i have the problem that the update of the meta data triggers the hook itself again. So it does never stop.

function change_unit_price($product_id)
{
    //test get data
    $_product = wc_get_product($product_id);
    $_regular_price = $_product->get_regular_price();
    $_sale_price = $_product->get_sale_price();
    $_meta_data = $_product->get_meta_data();
    
    // test set value
    $_product->update_meta_data('_unit_price_regular', "898");
    $_product->save();

}
add_action('woocommerce_update_product', 'change_unit_price', 99, 1);

Does someone has a solution for this or is there a workflow i don’t know yet? This is my first try with wordpress plugins.