How would backing up help with that, though, assuming the backups are also encrypted?

I meant if I lose my encryption key I lose the data on the disk.

If they lose the key they lose the data in the backups, too. So that concern is not a good reason to backup, in my eyes.

Then, if the backups are not encrypted, then doesn’t that undermine the value of encrypting your drive/user data partition in the first place?