I’m not expert on encrypted drives but I see no partitions? How about:
$ ls -Al /dev/sd* or perhaps $ ls -Al /dev/nvme*
$ grep -srl DEVTYPE=partition /sys/devices
No need to publish any output here but, as said, I see no partitions within your post/output and doubt that can help any further (as it is too late for me now, although I like to learn something here).
I’m wondering if cloning the drive to an external device, then mounting on the external device would get the file system to see the mounted, decrypted data?
At this point, I just don’t know what to do. The data is there. The drive mounts. I just don’t know how to get the file system to see it and allow me to navigate to it. (Nor what might have messed it up.)
Did you already booted into a Live Environment (if you can open/read this Luks drive)? Also, if you are using Nautilus do you have seahorse-nautilus package installed? Which filesystem(s) are on this drive/volume?