I think you want Slackware. It's about as close to a BSD system that linux gets, no systemd...install i3wm and you've got mostly what the commenter above described.

I used Slack for many, many years both as a personal OS and a production server. It's rock solid, fast, and lean. It's not easy though, and you're going to be doing a lot of compiling from source and package management by hand. These are the trade-offs.