There is no recipe for the terra arrows because they are from another mod (calamity). But I don’t understand why the infinity only work for bullets when they are in a stack and not arrowsIt's always either 3,996 or 999 for any stack of anything. Make sure that you have a workbench and crystal ball near each other, just in case it's one or the other. A lot of infinity related items use the crystal ball.
Though do show the item to the guide just in case the recipe isn't quite what we expected.