The Slackware community has produced about 8 package manager front-ends that handle dependency resolution, so it’s not an issue at all and hasn’t been for over a decade. The big thing with Slackware is an emphasis on simplicity of design over ease of use and an expectation that the user will make all the decisions regarding how their system is maintained. I love it, use it on my main machine (Void on my laptop, Ubuntu on my server). It’s taught me a lot about operating systems in general and Linux in particular, and it lets me do whatever I like. I use sbotools and flatpak for my 3rd party software, the former being a ports-like interface to slackbuilds.org (like the AUR for Slackware, but far smaller and with a lot more quality control). Works great, no surprises, boots fast, rock solid and dependable.