Linux for the Airheaded Layman?

I have tried to learn Linux for ages, and have experimented with installing Arch and Ubuntu. Usually something goes wrong when I try to set up a desktop environment after installing Arch in VirtualBox. KDE gave me a problem where I couldn't log in after getting to the point where my username was displayed in a similar format to how it is for Windows. My end use case is to help keep my workflow more organized than haphazardly throwing files somewhere on my desktop or in a folder nested somewhere that I'll just inevitably lose :(

Somehow after all this time, I feel like I actually understand less about my computer and what I need to understand regarding its facets. Is it an unrealistic goal to want to eventually run a computer with coreboot and a more cybersecurity heavy emphasis? I'm still a noob at this and any advice would be appreciated!