This seems like a fairly easy idea to test without any capital investment but a bike and a landing page.
1. Throw up landing page explaining service
2. Have people put in orders via email or form submission
3. Ride bike to grocery and deliver items
4. Collect cash or use Square upon delivery
Market test complete. Failure with minimal $ committed.
It worries me that an idea that could be done for so little capital is able to raise money. These are heady times.
Question to OP: did you ever consider targeting caregivers who would like to cook for their loved ones but can't leave the house for significant periods?