US Consumers pay in fungible dollars, and so if your company paid for three pizzas eaten by an AWS team, and I paid for 1 ounce of Maersk fuel oil, and our Starbucks venti latte purchases paid to rethatch Juan Valdez's hut, who can even trace the serial numbers on our $1 bills?

A tariff is included in the cost of a product by the final seller. The final buyer ultimately pays the tariff.

It doesn’t matter who sends the actual tariff payment, it gets priced into the cost of the product.