One solution here is to move from 'at will' employment explicit 'tours of service' [0]. If you had hired a bunch of staff in June 2020 under a 2 year contract, with renewal not guaranteed or even expected, you essentially have a built-in mechanism to match employment to the at-home shopping surge.
If you had thought the pandemic would just be one year, or three, you could write the contract accordingly.
This is probably pretty hard for roles where it takes a while to get up and running, but not so hard for, e.g., sales and operations roles.
I personally would appreciate this because every 1-2 years I yearn for a long break.
[0] https://forum.effectivealtruism.org/posts/waeDDnaQBTCNNu7hq/...