I highly recommend building an LFS. It was one of my first big personal endeavors with computers. In the article, the author says they didn't learn stuff that'll _necessarily help them in their day-to-day_, which I can echo, but I definitely learned a lot about different commands, the file structure of linux, `hier`, changing root, cross-compiling, toolchain building... it's really an awesome and fun process, and is especially satisfying when you manage to boot into it for the first time. I will say I'm much less fearful of the GRUB CLI than I used to be ;)