@Hdg:
For problem 1:
You can get command line by SSH, as the tty1 you see on the HDMI output will not take any inputs.
You do this by ssh umbrel@umbrel.local or ssh umbrel@<ip_address> if the umbrel.local does not work (for example in my network it is umbrel@192.168.0.102. The keyboard/mouse input is disabled for security reasons on tty1. The password should be the one you set up with the dashboard, or if you haven’t set it up yet, the default password is moneyprintergobrrr
For problem 2:
For the cloning from 500GB to a 1TB SSD, I’m not entirely sure about Macs, but I tried googling it… and it is for the computer itself, hopefully you can figure it out somehow. I have instructions for Windows, but it wouldn’t be any help since you got a Mac, but here it is: [GUIDE] Cloning or Migrating SSD/HDD (Windows)
Problem 3:
While it is true that powering off the RPi can cause the SD card to get corrupted, but that should be ok, but you should be able to reflash the SD card, and then it’ll take the data off the SSD as it stores pretty much 90% of the Umbrel software (Umbrel devs, correct me if I’m wrong) – and the remaining 10% is to let the RPi be able to boot. I know we can just update the bootloader to the latest version and then enable USB booting and doing away with the microSD card… but it is for redundancy i my opinion.
Problem 4:
Umbrel is mostly web-driven UI, but yes you can access the underlying command line interface, see the answer to problem #1 for the access. Edit: The underlying operating system is identical to the Raspberry Pi OS Lite (the version without the desktop), and the way you explained it makes sense, the node is a server.