Slackware doesn't use it, and Patrick Volkerding recently got a Patreon account set up so Slackware 15.0 or 14.3 will hopefully be out soonish with updated packages. I'm writing this on 14.2 and have been running it since it came out with basically no issues. Also have it on a backup server, runs great.
Use Alpine or something then. I use Alpine as well on a server, OpenBSD on a server, slackware on a server, slackware on my laptop... There's some options. We even use Devuan to host OP's essay, although we'll eventually move to openbsd probably for other reasons.
In terms of package management... why do you need it? I have no problem maintaining everything with slackpkg and sbopkg along with slackbuilds.org. Sometimes it takes a while to find all the requirements for an application and add them to a queue, but once it's set up it's just sbopkg, click on update, upgrade, and you're good. It's pretty much rock solid once I get everything installed and I haven't missed package management much at all. My main gripe is the old packages in 14.2 but -current has a lot newer stuff. I don't mind waiting though.
I still don't entirely get the point of Devuan. I put Debian buster on a low-RAM embedded box, and since systemd eats up precious RAM I'd rather keep, I just switched to OpenRC with
apt install openrc && apt purge systemd
If I needed it, Debian packages elogind as well.
Rebooted and it worked perfectly. Now, I get that Debian doesn't really support OpenRC[0] (or sysvinit), and it could break in horrible ways when bullseye goes stable, or get removed entirely, but... I don't see why we need a fork before that happens? It seems like it's a lot of work to maintain a distro fork, when I feel like that effort could be more productively redirected to stronger maintenance and advocacy of OpenRC and/or sysvinit in Debian itself?
[0] Debian's openrc package hasn't been updated in a little over a year, which is indeed concerning. sysvinit does seem to be more actively maintained, though.
Iron grip, aggression, pushiness are needed to lobby systemd out.
Another important initiative is to not to let Poettering, Sievers and co. continue throwing new systemds onto distributives. A preemptive action is needed.
Help me..