I tried I guess it was SuSE back in the mid-2000's. It was good for an RPM distribution. I'm not an RPM fan though. I've seen the RPM repo corrupt itself on SuSE, Red Hat before the split they did when they created RHEL and later at work on RHEL (one place I worked where they used RHEL). Tried Ubuntu 2006 at home and have used it since then. Run KDE desktop on it.

The Firefox thing was a simple fix since I also don't use snap, I just downloaded the Firefox tar file and run it. Using Help About, it updates itself, fast and efficiently. No snaps needed. No Ubuntu repository needed.