I support the antix project for sure, but non-systemd can be a lil tough. Not that other init systems are inherently more difficult, just systemd is far more standardized/widely used and that helps with troubleshooting.
In general, following as many standards and defaults as you can is helpful when learning. Debian, Ubuntu LTS, RHEL, SUSE, and anything most things derivative of them. All get a person used to a certain set of commands and software, all have sane defaults, and all are stable.
I really like the stuff in the middle like midnight commander. Idk why, it’s just the best of both worlds to me.