This all seems unbelievably more complicated and prone to failure than just doing luks over mdadm. You could just skip this weird, arcane process by imaging the disks, walking them to where they needed to be, then slapping them into the other machine and mounting them as normal.

I do not understand making RAID and encryption so very hard, and then using some NAS in a box distribution like an admission you don't have the skills to handle it. A lot of people are using ZFS and "native encryption" on Archlinux (not in this case) when they should just be using mdadm and luks on Debian stable. It's like they're overcomplicating things in order to be able to drop trendy brand names around other nerds, then often dramatically denouncing those brand names when everything goes wrong for them.

If you don't have any special needs, and you don't know what you're doing, just do it the simple way. This all just seems horrific. I've got >15 year old mdadm+luks arrays that have none of their original disks, are 5x their original disk size, have survived plenty of failures, and aren't in their original machines. It's not hard, and dealing with them is not constantly evolving.

Reading this gives me childhood anxiety from when I compressed by dad's PC with a BBS pirated copy of Stacker so I would have more space for pirated Sierra games, it errored out before finishing, and everything was inaccessible. I spent from dusk to dawn trying to figure out how to fix it (before the internet, but I was pretty good at DOS) and I still don't know how I managed it. I thought I was doomed. Ran like a dream afterwards and he never found out.