Ideally you would never have to because you just have the two people come up with their part of the password and then initialise the LUKS partition together. Sorta like a key ceremony

You can also just split the password for a single LUKS into two parts and give one each to the two people :D

Hey, not sure how in depth your linux/docker knowledge is. Please disregard if irrelevant. I would recommend you pick a fixed mountpoint for the drive and set up a systemd service to mount the drive for you (systemd .mount file). Then you add an extra line “RequiredBy=docker.service” (look for systemd RequiredBy) This way the drive always has to be mounted by the system before docker is started and should always be visible before you start a container.

Hope this helps :)

Honestly my recommendation would be to start off with some microcontrollers/Raspberry Pi and some breadboards and go from there. That way you can uhhh trial and error your way to something that works and worry about the “engineering” part later, when you have gotten your feet wet :D There are some simple Arduino starter kits for example that give you the basic things + a bunch of sensors and motors to play with. I got started myself with the Elegoo Arduino Starter Kit (~50€). Along the way it’s probably going to be helpful to look up some course on electronics basics, specifically digital circuits and then analog circuits if you’re feeling adventurous.