That would be the stable distribution, the current distribution which is the basis for the next release (now 15.1) was last updated today. It is also highly stable relative to other distributions including Arch so for I would recommend it to anyone with some knowledge of Linux.
Arch is great of course, and the Arch Wiki is one of the best general resources for Linux out there.
I used it as my daily driver for 2 years, only stopped because I got an Apple silicon machine and went all in on Mac for my day to day.
Slackware is fantastic. What I like most about it is the tiny mental footprint - you can grok how it works without any trouble, the distribution is basically a bunch of shell scripts and a package manager. It’s batteries-included which is different to some distros today - the concept of a lean Slackware machine is neither helpful nor particularly useful, you install the entire distro and use what you need. The package manager doesn’t have built in dependency resolution, but this isn’t necessary for the distribution, and third party packages are reasonably easy to manage with other package managers (Slack-ish ones like slackpkg+, sbopkg, etc., as well as general use ones like Nix).
I highly recommend it at least to try. It is opinionated, but won’t get in your way if you want to change it. It is easy to use and the community is friendly. Try getting Liveslak and giving it a spin.