Proprietary applications tend to have trouble with the wide variety of
Linux distributions and their variance. That's probably why more are
going to Flatpak and/or Snap for distribution, to be able to distribute
a single image that runs on Linux. Those also have an advantage of
running applications in a limited-access sandbox (so you don't have to
trust the proprietay applications as much).
It does look like Slack has an official Snap distribution, so that's an
alternative to their RPM/yum repo.
--
Chris Adams <linux(a)cmadams.net>