Since I started delivering for Instacart some time ago, they have implemented something in their app that allows you to pick up any extra orders that people scheduled to work can't do.
Since then, I have never scheduled myself for shifts but rather just picked up any orders that I had time to do.
I really like the flexibility this allows and it means you can choose to do delivery only orders or do orders that include having to shop for the items.
This way, if the distance for delivery is too far, you can just reject the order and it doesn't affect your stats at all.
I don't know if this feature is available everywhere, but it is in the Fargo, ND market and I really like it.