Actually Apple does not ship internationally and if you are using a shipping forwarder they will use their address for determining the sales tax. If they determine you are using a shipping forwarder they will cancel the order.
Amazon does not have any physical stores where they sell iPhones which is why you don't pay sales tax but they also are not supposed to ship internationally. They are violating Apple's rules.
Do make sure the carrier you plan to use in Latin America supports eSIMs because the US 14 series do not have a physical SIM slot. Also if you need any hardware repairs you will have to return to the US.