I’m not saying it would be practical in your case, but you could definitely carry 6 weeks of groceries on a cargo bike (ebike would be better given the load though). Hell, you might even be able to do that on a regular bike. I can fit at least 60 liters of groceries into my Portola, and that isn’t even including the top rear cargo rack. In an actual cargo bike, you could probably fit like 2+ months of groceries.