Hi my best team !
You could also add whatsapp notification with https://wassenger.com/ API as an alternative for SMS notification as most of customer do use a smartphone which means they have at least a whatsapp number.
Whatsapp doesn't flag number when template contain variable which means every notifications is customized for the customer (names, orders, price, delivery info )
Their entry plan is 19.99$ which far cheaper then direct whatsapp API and even more compared to Twilio on a volume basis of messages