I am using Kubuntu 21.10 and am trying to set up konsole the way I like it.
--I can create a new profile and set every detail as I like it. I can even set it as "default". After having done that, if I open a new window, it opens with the new settings.
--However, despite all the settings, when I start a new instance of konsole, it starts with the "Default" profile, which is "read-only".

I have two questions:
1) Where is this hardcoded konsole profile located, or how can I override it?
2) Why on Earth would someone think this is a good idea. Are they trying to make Kubuntu more like a Mac where the users can only use things in a way the developers imagine they would want to use it?

Thank you very much for any help.

I can't reproduce this here at all, I use my own profile and a new instance of Konsole opens with my own default profile.
You can check the konsolerc file located in ~.config/ if the Default Profile really reflects your settings

You're probably doing something wrong. I don't have that issue on any kde setup.