e2fsck checks only the metadata, it cannot know if data inside your files is corrupted or not. So I would use the old backup and think hard about what files could be needed and are newer from the corrupted image. Can be timeconsuming.
It might be that the SD-card was in some blocked state doing wearleveling or whatever, so maybe the image you made later is maybe correct. You could try to write it back and see if it boots.
But to prevent such issues, use Btrfs as rootfs. It has checksums for all data blocks and would have listed you in this case where which files the corruption is. It also also allows you fast incremental online backups, so every hour or so, what you want. And because Copy on Write, no problems with sudden powerloss, assuming it is not a bad or half-dead SD-card.
