I used CLFS (Cross-Linux From Scratch) once to bootstrap Linux on my SGI Indy, and I learned quite a lot from this. That was back in 2008 or so, so way before AI and extensive online guides for almost everything. It taught me how cross compilers work, what dependencies exist in the GNU toolchain, how the SGI boots, and much more.

Too bad Cross-LFS is no longer a thing. Then again, with all these microcontrollers and ARM and RISC-V systems today, cross-compiling is no longer as magic (and tricky) as it was back then...