The Arch Linux Wiki is an incredible resource, even if you're running another distro. Most of it is pretty universal (other than specific commands like the package manager), and it explains how everything functions and fits together. If I'm troubleshooting, it's always my first stop.

Just keep breaking stuff! It means your learning and trying new things, for the most part. Eventually you'll just break stuff less and less or know what to look for when something breaks. On that note do try to struggle with something a little bit before rolling back or reinstalling.

Depends on what you're breaking I guess. If it's DE stuff, kernel stuff, etc. Usually I just find a good YouTube tutorial if I want to learn something new and don't know what I'm doing.

Getting comfortable with manpages and regex will get you pretty far, this is a really great resource for beginners (available for free as .pdf):

https://linuxcommand.org/tlcl.php

I would recommend reading the manuals yes. Their are many manuals and not all are equal. The man pages can feel a bit strange as they list everything the software can do. To learn I found the archwiki to be better. (Also info manuals but many people are weirded out by the controls used to read these.)

Also don't blame yourself for reinstalling if you mess up. It's normal especially if you need the computer to actually work in a timely fashion