I use Debian for my personal desktop, and I fully understand where you are coming from, I keep a terminal window open 24x7 for various tasks that cannot be easily done via GUI. But have you tried Linux Mint? I have had excellent luck using it for people like your mother (or my wife lol) and been able to get the desktop system fully operational without ever touching a command line. Non-free wifi drivers and all. The folks at Mint have done an excellent job of making not only a beautiful looking and good performance desktop, but also one that does the hard stuff automatically for those that are not techs.
Wow you did have a bad experience. I actually do remember running into the secure boot and the wifi drivers issue on a system once, I guess we get to blame the secure boot people for that, just as many others have done, they have chosen to only fully support Windows, which causes Linux and other OSs problems sometimes. Secure boot DOES work, but not if you have to use proprietary driver modules in the kernel, because apparently secure boot can't authenticate them.
df19127ead