On Android (which I think you must be since you mention backup to Google Drive?) the otherwise encrypted database is an unlocked sqlite db while the app is running.

Spent way too long diving into that rabbit hole one time when I switched phones, activated WhatsApp without thinking about it on the new phone (and didn't restore, or switched back and forth, or something) and refused to go on with a history split between two devices. Eventually managed to merge the databases, put it on the new phone, and reinstall (since you can only restore during first-time startup...). Absolutely not worth the time it took, but I was stubborn.

I'm not saying that isn't shit, or that WA expects you to do that, just that if you want to, it can be done.