Feel free to use decaf coffee in the Frappuccino. You could also use espresso if you prefer. Or you can leave the coffee out altogether and simply use more oat milk. According to the Starbucks ...

Everyone has their own unique way of ordering iced coffee. "With cream and sugar," "with oat milk," "half-caff," "decaf," "cawfee filled halfway up the cup, top it with 2 puh-cent milk" (in that ...