Interesting that you're saying the BSDs use something sysvinit-based. i never saw any runlevel idea there, which i thought was the primary marker of sysvinit? arch used to have an init system that felt very BSD-like. unfortunately they moved to systemd, and i went to void, but not happy with the init system there either. using linux used to be so much easier when "learning an init system" wasn't really a thing yet.