What does the locale command say? Have you tried to change a font?

Yes. Just partition the drive manually, install packages with debootstrap, bind-mount /proc, /sys and /dev, chroot into it and install a bootloader. If you don’t understand what I say, you have to run an installer, possibly in a VM.

It is documented in libapt-pkg-doc (/usr/share/doc/libapt-pkg-doc/method.html/index.html).

Why you say “Linux” when you mean “Fedora”?

If I’d decide to implement something like this, I’d consider two options: local repo with file:// scheme or custom apt-transport. HTTP server is needless here. (But I’ll never do this because I prefer to rebuild packages myself if there’s no repo for my distro.)

There’s one case when you can’t avoid using command line. If you ask someone on Internet to help you, he will say you to type some commands. No window clicking, no screenshots will help. All GUIs are different, but CLI is (almost) always the same, and its output is well searchable. That’s why you see numerous command line listings in each topic discussing problems and could decide it’s impossible to use Linux without coding.

In depends on how dumb the user is. If you want to see drive C:\ and don’t want to learn why there’s no such a thing, forget about Linux (and any other OS except the only one you are familiar with). If you are ready to learn new concepts and just don’t want to remember numerous commands, that’s OK, just pick up a distro with advanced DE and graphical admin tools.

What does an ordinary RHEL admin do when something does not work?

“Easy to use” means that you do less and get more. Learning doesn’t count if you learn something once and then use the skills you obtained many times.

No, some piano plays are still harder than others, mo matter how long you practice. Editing text with vim is easier than with nano after some practice.

Why do you think so?

It is easier after you learn basics. Learning is not easy, but usage is.

Every day in my case, except holidays.

Vim (or emacs, or any other advanced text editor) is much easier to use than nano when you need to do something more complex than type couple of lines.

Security fixes are backported to ESR releases so they are not less secure than bleeding edge.

You don’t have to clean your ~/.cache every now and then. You have to figure out which program eats so much space there, ensure that it is not misconfigured and file a bugreport.