You could line a container with foil, wax paper, cellophane or parchment paper, add food and freeze.
Once the food is frozen, remove it from the mold, fold the liner closed, label and stack.
Foil can be recycled at a scrap
yard, wax paper used as tinder, cellophane is made from
trees and is biodegradable, I'm not sure about parchment paper...
There are also a lot of square sided stainless steel container's available used, from the foodservice industry.
They make all kinds of lids for them, including silicon.
I have a box of them, purchased as surplus, and they have no off gassing smell.
If you never subject them to heat, I think they would last indefinitely.