“I don’t even have enough pantry and refrigerator space for that.”
Get rice & beans, or mashed potatoes in a box and beans. Get whey protein powder, which is still widely available. And a multivitamin with minerals. Some water, which you can put in containers from the tap right now.
You can go months on that if you have to. More carbs than I personally would prefer, but you’ll have plenty of time to work it off exercising.
You can even probably order most of that for local delivery.
You can also get cans of Chef Boy-Ar-Dee stuff if there are any left at the store. Make prepping fun! And since they’re in cans, if you run out of bleach, you can just quarantine them somewhere for the next 3 days.