I thought this too, but unfortunately in terms of modding and general use they are very limited, afaik. When I looked into it, it boiled down to: There’s an sdk to develop stuff for it and you can get root access but good luck trying to replace the os or anything like that. That being said, this is what I remember from ~2 years ago, so if it can be customised more now, please let me know. I kinda bought 2 in hopes of being able to do that :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.
It seems to be more for if you actually want something that makes use of the screen and gamepad input and then you can launch it from the UI.
https://github.com/ValveSoftware/steamlink-sdk