How do i obtain certain registery keys or options in Windows to be able to use it in command-line script?

Question

Recently i posted a question about disconnecting a screen from Windows and automating this task, but i got no really response how to achieve it.. (ref)

Then it got me thinking, I must be an easy way to obtain certain options in windows via registry keys, for example if somebody can create an app (Windows Settings) and it allows you to change particular option on and off it must call something to do it or swap some values in registry, right?

That's my goal, i want to capture this moment where particular setting is changed, this way i can get something like .{ED7BA470-8E54-465E-825C-99712043E01C} and work with it further (this above is actually god folder in Windows)

Maybe I am wrong, but i know I am missing something, there are people creating great scripts in .reg and real question is how do they get these keys in a first place to form script?