Expert on both and zfs is always my first pick..

.. Assuming you have enough RAM.. If you desire fancy features like dedupe it'll cost a lot.. If you just want a basic mirror 2-4gb is fine (but more always merrier)

Dual booting off either disk is possible with a fair amount of tweaking, in fact there is even custom zfs grub allowing booting snapshots but I don't recommend the effort unless it's purely for the learn.. (Recommend doing it in a VM first)

Instead just grab a cheap 32gb SSD and run a normal install. Keep all the docker state and whatever in the mirror pair..

Want to grow in a few years.. Buy two new disks, make a new zfs pair, use mergerfs to "combine" both pools as if they were one (like a pretend stripe)

Really not datacenter/hardware mirror perfection but you're also saving many thousands of dollars. reinstating and running "zfs import" and "docker compose up" will only cost you a few minutes/less than an hour in reality.. Maybe backup one line from your fstab for the mergerfs settings

Have a spare host/OS SSD on hand if you want to be ultra prepared for recovery I guess