I always find it funny when people do that with Windows, Mac, and Linux. It completely misses the fact that Linux can be all of these things.
OS for kids: https://www.sugarlabs.org/
Just works: https://www.linuxmint.com/
Fuck around and find out: https://www.linuxfromscratch.org/
Minix is not a Unix fork, it’s a Unix-like (along with Linux). Tanenbaum wrote Minix from scratch as an educational tool. It’s userland these days is basically NetBSD but at the kernel level, Minix has a very different architecture to Unixes.