A spreadsheet is NOT a database! Argh! As a person who gets asked to fix these kinds of projects once they hit a wall (performance/concurrency/etc) and then have to migrate them to a proper DB platform, just stop it! Put it on in a DB up front and save some poor developer their sanity. Please.
Imagine if you had a Google Sheets adapter for ActiveRecord. You could start any project this way and it would be super easy to then migrate it to another supported DB.