Chimera is developed by a former Void maintainer. It's still in its infancy compared to the two main "KISS" distributions (Alpine and Void) but it looks promising, especially thanks to dinit, which like S6 is what systemd should have been.

https://chimera-linux.org/docs/configuration/services

Then if a Linux kernel isn't a strict requirement, there's obviously NetBSD, from which Void takes inspiration. At last it's "the real thing" and not some adaptation, and a very underappreciated and overlooked Unix.