There's sizable differences though. Uber / Lyft enforces several standards about your car, it's presentation, etc. Uber / Lyft also punish you for declining a ride. Uber / Lyft don't show you the complete route, or the complete fare, until you have actually picked up the passenger(s).
InstaCart doesn't care what your car looks like. It shows you the pickup location as well as the final delivery location. InstaCart shows you exactly what you'll earn, including any pre-tip the customer has offered (granted, there has been issues with customers tip-scamming people). There's no detriment to not accepting a delivery.
Uber / Lyft have a lot more of an "employee-like" relationship with their people than InstaCart / DoorDash do.
The only possible interpretation of any research whatever in the `social sciences' is: some do, some don't. -- Ernest Rutherford