How can I recover an ext4 filesystem corrupted after a fsck?
My preferred tool for filesystem data recovery is UFS Explorer.
I do not know how the LUKS encryption will impact this, but download an evaluation of UFS Explorer and try the normal best-practices. Run it against your image and see if things appear to be more recoverable. The tool will provide you with a good view of the directory structure and give some ability to search for data.
Also see: How to recover XFS file system with "superblock read failed"