I do all my commuting and grocery hauling on a bike, and I work at a bike shop selling and repairing all kinds of bikes including e-bikes.
@David3's advice to buy from an actual store is sound. If you buy a bike online you'll either have to pay a bike shop to put it together (and they'll likely charge extra because e-bikes are more work to build and you didn't buy the bike from them) or you could put it together yourself. It's really not that hard but it will take a lot of time if you haven't done it before and don't have a bicycle workstand, plus new bikes almost always need their wheels trued and brakes adjusted. I can't tell you how many times I've seen bikes put together wrong.
Another reason to avoid internet e-bikes is because most of them are junk. Low-quality everything that even with the right tools and experience can't be properly tuned. If you experience a malfunction in the computer/sensors/motor on some off-brand system there's not much you or a bike shop can do besides clean the connections and cross your fingers. If it's a bike I've sold I can run diagnostics, update the firmware, and have access to replacement parts.
If you're interested in buying a bike
for grocery hauling, as opposed to purely recreational riding, get one with a standard double diamond frame design. Step thru frames generally sacrifice handling for comfort and can wiggle around like a wet noodle when loaded down. If you're riding in traffic you need to prioritize handling - even more so if you're riding on the sidewalk where "traffic" is super unpredictable and you'll be dodging fire hydrants, opening doors, clueless people and their dogs etc (honestly, bikes don't belong on the sidewalk). Those cruiser style bikes which put you in an upright body position are the worst for handling, accelerate poorly - even with a motor it makes a difference - and make it harder to look over your shoulder for oncoming traffic. Avoid anything with rear suspension. Front suspension is totally unnecessary but not a deal breaker...just make sure it's an air spring instead of coil, you can add more air to compensate for the added weight of groceries but a coil's spring rate is fixed. Tires wider than 2.2" are pointless, skinnier than 38mm will be a harsh ride and more likely to pinch flat. Wheels need to have double-wall rims, no fewer than 28 spokes. Disc brakes...any e-bike with rim brakes is probably a death trap.
You'll want a high-quality rear rack...no matter how stiff your frame is, if the thing your groceries are attached too is wobbly your whole bike will wobble in response. Avoid bags/panniers that rely on "soft" connections like velcro straps. Pack your heavy stuff down low, towards the front, and inboard.
Okay I could go on all day but point is if you buy an e-bike for utility riding make sure it's decent quality, with the necessary design and features, from a local retailer who can help with any issues. There's a lot of junk e-bikes out there so beware. Of course if you have the fitness the same money will buy you a much better non-motorized bike, in which case any mid-level touring bike will be pretty ideal.